Seaweed Flora of the European North Atlantic and Mediterranean

Abstract

Algae, like most vegetables, have cells with pigments that allow them to perform the photosynthesis. These organisms have a wide geographical distribution, colonizing various sites, but always linked to the presence of water. They can be found floating in the water, on wet rocks, walls, or in association with other organisms, as in the case of lichens, in association with fungi. They are particularly abundant in lakes, rivers, and seas, occupying the euphotic region (or photic), i. e., up to lower penetration of light effective for the realization of photosynthesis of algae (up to $200\mathrm{m}$ deep). Those that live in water can be planktonic (microalgae) or benthic (macroalgae). The former are small and live suspended in water (microscopic), whereas the latter remain fixed to a substrate (usually rock), are larger in size (macroscopic), and may reach $50\mathrm{m}$ in length. Seaweeds inhabit the oceans more than $2000\mathrm{million}$ years and are used as food by people in Asia since the $17$th century. Today, seaweed is used in many countries for several purposes: directly as food, phycocolloids extraction (carrageenan, agar, and alginate) used in the pharmaceutical, cosmetic, and food industries. Algae are also used in the extraction of antiviral, antibacterial compounds, and biofertilizers. The larger or macroscopic algae, called macroalgae or seaweed, are mainly found in three of the algal taxonomic groups: Chlorophyta (green algae); Rhodophyta (red algae); and Phaeophyceae (brown algae). In this chapter, the main European seaweed flora and their biotechnological potential are listed.

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1 Marine Macroalgae (Seaweeds)

Algae, like most vegetables, have cells with pigments that allow them to perform the photosynthesis.

Algae have a wide geographical distribution, colonizing various sites, but always linked to the presence of water. They can be found floating in the water, on wet rocks, walls, or in association with other organisms, as in the case of lichens, in association with fungi.

They are particularly abundant in lakes, rivers, and seas, occupying the euphotic region (or photic), i. e., up to lower penetration of light effective for the realization of photosynthesis of algae (up to $200\mathrm{m}$ deep). Those that live in water can be planktonic (microalgae) or benthic (macroalgae). The former are small and remain suspended in water (microscopic), whereas the latter remain fixed to a substrate (usually rock), are larger in size (macroscopic), and may reach $50\mathrm{m}$ in length [1].

1.1 Role of Algae in Nature

Algae are primary producers, i. e., they are able to produce oxygen and organic compounds that serve as food for other living beings, through the process of photosynthesis, using sunlight, atmospheric ${\mathrm{CO}}_2$, and inorganic substances present in water. Algae are, in fact, fundamental to food chains of all aquatic ecosystems.

1.2 Main Taxonomic Groups of Benthic Marine Algae

The coloration of seaweed is the visible expression of the combination of different cellular pigments. Thus, the phyla and classes of macroalgae are essentially defined in practice by their particular pigment composition.

Macroalgae are aquatic photosynthetic organisms belonging to the Domain Eukarya and the Kingdoms Plantae (green and red algae) and Chromista (brown algae). Although classification systems vary over time and according to the authors, it is generally accepted to consider that

• 1. The green algae are included in the Phylum Chlorophyta; their pigmentation is identical to that of terrestrial plants (chlorophyll a, b, and carotenoids);

• 2. The red algae belong to the phylum Rhodophyta, their photosynthetic pigments are chlorophyll a, phycobilins (R-phycocyanin and R-phycoerythrin), and carotenoids (β-carotene, lutein, and zeaxanthin);

• 3. The brown algae are included in the phylum Ochrophyta (or Heterokontophyta), class Phaeophyceae; their pigments are the chlorophylls a, c, and carotenoids, dominated by fucoxanthin, responsible for the brownish color [1, 2].

1.3 Marine Algae Morphology

The diversity of algae is extraordinary; one can find a multitude of morphological types according to their complexity, structure, and environmental adaptations. Macroalgae show a complex degree of morphological organization, with laminar, cylindrical, tubular, or crustose thalli.

1.4 Importance of Algae for Mankind

Today, seaweed is used in many countries for very different purposes: directly as food, phycocolloids extraction, extraction of compounds with antiviral, antibacterial, or antitumor activity and as biofertilizers.

About four million tonnes of seaweed are harvested annually worldwide. The major producers are China and Japan, followed by America and Norway. France used to import Japanese seaweed in the 1970s but 10 years later it went on to produce algae for food and biological products users. Contrary to what happens in East Asia, the West is more interested in thickeners and gelling properties of hydrocolloids extracted from seaweeds: carrageenan, agar, and alginate (E407, E406, and E400, respectively) [3, 4].

1.5 Historical Overview of Algae Use on Health Treatments

Historically, the algae have been used by coastal communities to prepare home medicines to treat various health problems. Such applications are the product of the empirical knowledge of many generations and, in most cases, their mechanisms are unknown. However, the current research, undertaken in order to analyze the components and causes which affect the proper functioning of our body, are already giving their first fruits. So, we know, for example, that the good results obtained with the use of Kelp (Laminaria spp.) in the treatment of goiter are due to the fact that the origin of this disease is a diet low in iodine, chemical element present in significant quantities in brown algae [3].

Green algae have been used as anthelmintics, astringent, and to treat gout. Brown algae are used in the treatment of rheumatic processes, arteriosclerosis, menstrual disorders, hypertension, gastric ulcers, goiter, skin diseases, syphilis, and as an anticoagulant. Red algae are used as anticoagulants, anthelmintics, and in treating gastritis and diarrhea [3, 5].

2 The Marine Algae and Their Biotechnological Potential

Over time, the need to find new paths in search of new sources of energy is evident and relevant, especially the methods independent of fossil fuels, because they will run out one day and have an increasingly higher cost of use, both in terms of economic costs but mainly environmental costs.

One way to achieve it is by taking advantage of the biomass from the cultivation of algae in the oceans and seas, which offer large areas available for that purpose, which does not happen on land, where farmland is occupied for the production of food. The algae can produce, for example, biodiesel and ethanol.

On the other hand, in recent years, several marine organisms have been confirmed as an important source of new compounds potentially useful for the development of chemotherapeutic agents. Previous investigations of the production of antibiotic substances by aquatic organisms point to these forms as a rich and varied source of antibacterial and antifungal agents. Over $15000$ novel compounds have been chemically determined. Focusing on bioproducts, recent trends in drug research from natural sources suggest that algae are a promising group to furnish novel biochemically active substances [6].

Seaweeds or marine macroalgae are the renewable living resources which are also used as food and fertilizer in many parts of the world. Seaweeds are of nutritional interest as they contain low calorie food but are rich in vitamins, minerals, and dietary fibers [7]. In addition to vitamins and minerals, seaweeds are also potentially good sources of proteins, polysaccharides and fibers [8]. The lipids, which are present in very small amounts, are unsaturated and afford protection against cardiovascular pathogens.

Seaweeds are considered as a source of bioactive compounds as they are able to produce a great variety of secondary metabolites characterized by a broad spectrum of biological activities. Compounds with antioxidant, antiviral, antifungal, and antimicrobial activities have been detected in brown, red, and green algae [10, 9]. There are numerous reports of compounds derived from macroalgae with a broad range of biological activities, such as antibacterial [11], antivirals [12], antitumorals [13], anticoagulant [14], and antifouling [15], antihelminthic and antifungal [16].

3 Taxonomy and Description of Marine Algae with Biotechnological Potential

3.1 Domain/Empire Prokaryota, Kingdom Bacteria, Phylum Cyanobacteria (Blue–Green Algae)

• Class: Cyanophyceae

• Order: Nostocales

3.1.1 Rivularia bullata (Poir) Berkeley ex Bornet & Flahault

3.1.1.1 Description

In general, blue-green algae (Cyanobacteria) are not easy to find on the coastline edge (Fig. 6.1). However, one species may be easily confused with a green seaweed (Chlorophyta), whereby described here. This species forms small globular vesicles, dark green, sometimes bluish, gelatinous, and elastic; adherent to exposed rocks, sometimes on Chthamalus spp. (Barnacles), together with Lichina pygmaea (Lichens), and may attain $5\mathrm{mm}$ in diameter [17, 2].

Fig. 6.1

R. bullata specimens on Chthamalus spp. (Barnacles)

3.1.1.2 Habitat

Grows on rocks of the upper littoral zone.

3.1.1.3 Distribution

NE Atlantic (Ireland and Britain to Portugal); Mediterranean; SW Indian Ocean; SW Pacific; Australia.

3.1.1.4 Uses and Compounds

Present antibacterial activity [18, 19].

3.2 Domain/Empire Eukaryota, Kingdom Plantae, Phylum Chlorophyta (Green Algae)

• Class: Bryopsidophyceae

• Order: Bryopsidales

3.2.1 Bryopsis hypnoides J.V. Lamouroux

3.2.1.1 Description

Plants in filamentous tufts, dull or dark green, $10\mathrm{cm}$ tall, are branching in an irregular, scattered pattern. Primary axes are highly branched. Fronds decrease in diameter with each successive division; branchlets form irregularly, undifferentiated from axes, constricted at base. Apices rounded; rhizoidal system fibrous, tightly woven [20, 21].

3.2.1.2 Habitat

Common near freshwater and nutrient rich outputs; attaches to hard substrates such as basalt, rocks, or rubble; forms delicate fronds which move with currents.

3.2.1.3 Worldwide Distribution

Atlantic Ocean, Mediterranean, Caribbean, Indian and Pacific Oceans, Australia.

3.2.1.4 Uses and Compounds

The primary structure of bryohealin and of lectin from Bryopsis hypnoides had little similarity with any known plant lectin, but rather resembled animal lectins with fucolectin domains [20, 22, 23]; Antifouling activity is present [24].

3.2.2 Bryopsis pennata J.V. Lamouroux

3.2.2.1 Description

Thallus filamentous, bushy, in tuft-like mats, to $10\mathrm{cm}$ high. Fronds feather-like, $8$–$15\mathrm{mm}$ wide, pinnately branched; lateral branches of uniform length, constricted at base where joined to main axes. Branchlets in two opposite rows on the upper half of branch, the lower half of branch is bare. The rhizoidal system is fibrous, tightly interwoven. Color is glossy dark green, often with light blue iridescence [25].

3.2.2.2 Habitat

B. pennata forms soft, feathery clumps attached to basalt rocks and rubble on shallow reef flats, in tide pools, and in the lower intertidal habitats of coastlines with low wave action.

3.2.2.3 Distribution

Atlantic Ocean, Mediterranean, Caribbean, Indian and Pacific Oceans, Australia.

3.2.2.4 Uses and Compounds

Bryopsis species are potentially invasive. Like the troublesome Caulerpa taxifolia, the genus produces chemical defenses that are toxic to most herbivorous organisms and easily reproduces vegetatively from the smallest fragments [25, 26]. The extracts of this seaweed have antibacterial [27, 28, 29], antifungal [29], anticancer [30], and cardiotonic [26] activity.

3.2.3 Bryopsis plumosa (Hudson) C. Agardh

3.2.3.1 Description

B. plumosa is a small, feathery species of green seaweed (Fig. 6.2). The thalli are erect, feather-like, and may reach up to $15\mathrm{cm}$ in height. It is easily recognized by its delicate branches. All branches are regularly arranged in two rows on opposite sides of the central filament. The lengths of the branches decrease gradually from the base of the plant. It is usually dark to mid-green in color [31, 32].

Fig. 6.2

Underwater photo of Bryopsis plumosa

3.2.3.2 Common Names

Evenly branched mossy feather weed; stoneworts.

3.2.3.3 Habitat

Not uncommon; in low littoral rock pools and in the sublittoral. Is an epilithic species that is usually found in a deep lower shore pool or subtidally in both sheltered and well-exposed habitats.

3.2.3.4 Distribution

NE Atlantic (Scandinavia to Mauretania); Mediterranean, Caribbean; SW Atlantic; Indian Ocean; NW Pacific (Japan, China); NE Pacific (Alaska, British Columbia); SE Pacific (Chile); Indo-Pacific (Philippines, Vietnam, Indonesia); Pacific Islands; Australia, New Zealand.

3.2.3.5 Uses and Compounds

Produces lectins with biological activity [23]; present antioxidant [33] and antimicrobial [34] activity, medicinal and, pharmaceutical uses [35].

3.2.4 Caulerpa cupressoides (Vahl) C. Agardh

3.2.4.1 Description

Erect fronds arise from stolons of up to several diameters in length, anchored to the substratum by rhizoidal structures. Fronds are usually rich forked toward the apex, and at base they are naked (usually three) rows of rounded or flattened, ovoidal to conically pointed, short branchlets with a distinctly pointed tip [32, 36].

3.2.4.2 Habitat

On rocks in the tidal zone at depths of $40\mathrm{m}$ depth.

3.2.4.3 Distribution

NE Atlantic (Canary Islands); Caribbean; NW Pacific (Japan, China); West Pacific (Philippines, Indonesia); Pacific Islands; Australia.

3.2.4.4 Uses and Compounds

This seaweed is reported to be edible, to have antibacterial [37, 38, 39, 40], antifungal, antioxidant [41], anticoagulant [41, 42], analgesic [43, 44] anti-inflammatory [43, 44], and antithrombotic [45] properties, and used to treat high blood pressure. However, some Caulerpa species produce toxins to protect themselves from browsing fish. This also makes them toxic to humans [36].

3.2.5 Caulerpa peltata J.V. Lamouroux

3.2.5.1 Common Name

Big parasol green seaweed.

3.2.5.2 Description

This seaweed has structures that look like fleshy umbrellas, with a thick circular portion (about $1$–$1.5\mathrm{cm}$ across) on a little stalk. These little umbrellas emerge along the length of a stem that creeps over the surface; bright yellowish-green to bluish-green color [32, 46].

3.2.5.3 Habitat

Found on shady rocks or dead corals in infralittoral zones along moderately wave-exposed shorelines. Caulerpa peltata grows in tide pools, on lower intertidal coral reefs covered with sand or on soft muddy.

3.2.5.4 Distribution

Widely distributed in tropical seas; Atlantic Islands.

3.2.5.5 Uses and Compounds

This seaweed was reported to be edible and used as medicine for its antifungal properties and has ability to lower blood pressure [46, 47, 48], it is also reported to have larvicidal [49, 50], antiplasmodial [51], citotoxic [52], immunomodulatory [53], antioxidant [52], antimicrobial [40, 54], and anticoagulant [55] properties. This species was evaluated for producing biodiesel [56].

3.2.6 Caulerpa prolifera (Forsskål) J.V. Lamouroux

3.2.6.1 Description

Fronds leafy, flat, with a distinct slender stipe and entire margins, at times undulating, oval to longitudinal, spatula-shaped or linear oblong, tapering toward the base, at the apex also narrowing but bluntly rounded (Fig. 6.3). Occasionally, more of these dark-green photosynthetic organs emerge from the stipes as well as from the margins or surfaces of the blades. The sparsely branching, relatively thin ($1$–$2\mathrm{mm}$) but wiry stolons are widely spread out, often extensive areas colonizing in this way; rhizoids in intervals of $0.5$–$2\mathrm{cm}$ [32].

Fig. 6.3

Underwater photo of Caulerpa prolifera

3.2.6.2 Habitat

On sandy or muddy bottoms in sheltered lagoons, only slightly below the low water mark, often among Seagrass; but also on little wave-exposed rocks at depths of several meters.

3.2.6.3 Distribution

NE Atlantic (S Spain to Canary Islands), Caribbean, Mediterranean; Indian Ocean, SW Pacific (Philippines).

3.2.6.4 Uses and Compounds

Commonly used in aquaria, to which it is well adapted [32, 57], this species produces Caulerpenyne, an acetylenic sesquiterpene, which is specific to Caulerpa, as described by Amico etal [58, 59] for C. prolifera. This seaweed is reported to have antibacterial [40, 60, 61], antialgal [61], antifungal [62], antifouling [63], antiproliferative [64], antioxidant [64, 65], anticoagulant [64], and larvicidal activity [66].

3.2.7 Caulerpa racemosa (Forsskål) J. Agardh

3.2.7.1 Common Names

Sea grape; green caviar; grape caulerpa.

3.2.7.2 Description

It is a bright green seaweed that resembles long skinny vertical bunches of tiny grapes. It can be very similar in appearance to Caulerpa lentillifera, though the latter tends to produce denser bunches (though this line can be smudged when Caulerpa racemosa grows in wave-exposed waters and develops shorter, stronger branches than normal). C. racemosa is quite variable in morphology and has many different growth forms that have been identified and named. A horizontal stolon which is attached to the sediment (usually sand) by descending rhizomes gives rise to erect branches at every few centimeters. These branches can reach as much as $30\mathrm{cm}$ in height and produce a large number of stalked branchlets which vary in shape from spherical to ovate to disk-shaped, sometimes flattening on top or forming icecream-cone-type shapes. These plants are coenocytic, which means that the entire plant is made up of one giant cell with many nuclei and no cross-walls. It is mainly due to this characteristic, any part of a C. racemosa plant that is fragmented, even tiny bits of tissue, can regenerate to form entirely new plants [67, 68].

3.2.7.3 Habitat

Forms intertwined mats in tide pools and on reef flats. Horizontal runners tightly anchor mats to rocks and sand and in calm to moderately heavy surf areas.

3.2.7.4 Distribution

Eastern Mediterranean; Caribbean, Indian Ocean, NW Pacific (Japan, China), Indo-Pacific (Philippines, Vietnam); Pacific Islands; Australia, New Zealand.

3.2.7.5 Uses and Compounds

C. racemosa is grown commercially in the South Pacific, and harvested wild in other areas [67]; edible seaweed, eaten as salad in Polynesia and the Marquesas [32]. C. racemosa, like C. lentillifera, is used commonly in Asian and Island cuisines. It is often used fresh and raw as a salad vegetable and is desired for its peppery flavor which also makes it ideal for use in sauce making [69]. This seaweed is common in the Phuket market of Thailand where $10$–$20\mathrm{kg}$ of fresh C. racemosa is sold per day [67].

C. racemosa also contains compounds which function as mild anesthetics, which gives the seaweed clinical value. Traditional medicine of the Philippines uses C. racemosa to lower blood pressure and to treat rheumatism [67, 68]. This seaweed is reported to have antibacterial [39, 60, 70, 71, 72, 73], antiviral [72, 74, 75], antifungal [71], insecticidal [76], antioxidant [77, 78], anti-inflammatory [73, 79], anticoagulant [74], analgesic [79], hypolipidaemic [35, 80], hypoglycemic [81] and antitumor [77, 82] activity.

3.2.8 Caulerpa taxifolia (M. Vahl) C. Agardh

3.2.8.1 Description

Plant with widely extending, smooth stolons, about $1\mathrm{mm}$ in thickness; rhizoid-bearing branches downward and photosynthetic branches growing upward. Erect sections short-stiped and feather-like: the unbranched or sparingly branched axis is covered pinnately with $3$–$6\mathrm{mm}$ long and $1\mathrm{mm}$ wide, flattened and upward-bending branchlets. These are compressed, slightly constricted at the base and narrowing toward the mucronate tip [32].

3.2.8.2 Common Names

Killer algae; Aquarium Caulerpa; Folia feathery green seaweed.

3.2.8.3 Habitat

In sunny locations on sheltered shores, most common in shallow water on sand, mud and rocks, but also in up to $30\mathrm{m}$ depth.

3.2.8.4 Distribution

Widely distributed in warmer seas, NE Atlantic (Canary Islands); W Mediterranean; tropical E Atlantic (Ghana); Caribbean; Indian Ocean; NW Pacific (Japan, China); W Pacific and Indo-Pacific (Philippines, Vietnam, Indonesia); Pacific Islands; Australia.

3.2.8.5 Uses and Compounds

This green seaweed is reported to be edible [83], to have antioxidant [84], antibacterial [83, 85, 86], antiviral [87], nematicidal [88], and antifungal properties, and used to treat tuberculosis and high blood pressure [83]. However, some Caulerpa species produce toxins to protect themselves from browsing fish. This also makes them toxic to humans [83]; caulerpenyne from C. taxifolia which is cytotoxic toward several human cell lines and as such has anticancer, antitumor, and antiproliferative properties [35, 89, 90].

3.2.9 Codium adhaerens C. Agardh

3.2.9.1 Description

Spongy thallus, green light, prostrate, irregularly shaped, and presented with the appearance of a plane carpet firmly fixed to the substrate (Fig. 6.4). It consists of entangled coenocytic filaments and a finished surface by narrow and elongated utricles that are difficult to separate. Firm, gelatinous texture, and smooth to the touch [91].

Fig. 6.4

Cushion-shaped, dark green, strongly adhered to the rocky substrate (Codium adhaerens)

3.2.9.2 Habitat

Perennial seaweed that can be found on exposed or protected shores under low light conditions, being located mainly in vertical rock faces and gaps.

3.2.9.3 Distribution

NW Atlantic (common on European bordering countries), Atlantic Islands (Azores, Canary), Africa, Asia, and Australia.

3.2.9.4 Uses and Compounds

Have vermifuge [92], antidiabetic [93], antibacterial [94], and antiviral [95] properties.

3.2.10 Codium bursa (Linnaeus) C. Agardh

3.2.10.1 Description

Thallus a spongy sphere with a velvety soft, shiny surface; becomes more flattened when increases in size. The internal branched filamentous network becomes looser with increasing size of the sphere, the space fills with water and the surface becomes indented; anchored to substratum by felted filaments [32].

3.2.10.2 Habitat

On rocks, probably prefers sheltered locations; in the infralitoral up to $10\mathrm{m}$ ($-$ $50\mathrm{m}$) depth; often in drift.

3.2.10.3 Distribution

NE Atlantic (Ireland to Canary Islands); Mediterranean.

3.2.10.4 Uses and Compounds

Have antifungal [62], antibacterial [96], and antiplasmodial [97] activity.

3.2.11 Codium decorticatum (Woodward) M. Howe

3.2.11.1 Description

Very large, dichotomously branched erect thallus, dark green: from a crustose base rise one to several, up to more than $1\mathrm{m}$ long ribbons, regularly forking, rounded-flattened ($0.5$–$3\mathrm{cm}$ wide) and usually visibly compressed at the bifurcations, stretched out like webs, wedge-shaped, and over $6\mathrm{cm}$ wide at that point [32, 98].

3.2.11.2 Habitat

Inhabits shallow muddy bays and harbors, usually during summer months.

3.2.11.3 Distribution

NE and E Atlantic (Spain to tropical W Africa), Mediterranean; Caribbean, SW Atlantic (Brazil, Uruguay); Indian Ocean; Hawaii; Antarctica.

3.2.11.4 Uses and Compounds

Have antibacterial [100, 99], antioxidant [101, 102, 65], antiviral [103], larvicidal [104], antifungal [105], and antitumor [106] activity.

3.2.12 Codium fragile (Suringar) Hariot

3.2.12.1 Common Names

Dichotomous sponge tang, Forked felt alga, Sea staghorn.

3.2.12.2 Description

Dark-green alga, ranging from 10 to $40\mathrm{cm}$ high and consists of repeatedly branching cylindrical segments about $0.5$ to $1.0\mathrm{cm}$ in diameter, and its branches can be as thick as pencil. The segments look like dark green fingers. Its holdfast is a broad, sponge-like cushion of tissue. The tips of segments are blunt and the surface is soft, so it is sometimes mistaken as a sponge. Its body consists of interwoven, filamentous cells with incomplete cross-walls forming the inner part of the branches [107, 108].

3.2.12.3 Habitat

On rocky shores from the upper intertidal rock pools down to the lower intertidal.

3.2.12.4 Distribution

C. fragile is native to the Pacific Ocean in the Sea of Japan, and from Alaska to Baja California, Mexico. Its range has extended southward to South America, on the coasts of Chile and Argentina. It grows along nearly the whole coastline of the eastern North America, from the Gulf of St. Lawrence in Canada to North Carolina. It can be found in the Mediterranean and Adriatic, including the coasts of France, Spain, and Corsica. C. fragile ranges from Scandinavia to the Gulf of Gascogne and to the Canaries Islands. It has also been recorded in the Orkneys, Scotland, Ireland, Wales, and England. It can even be found in Australia, Antarctica, and southern Africa [107].

3.2.12.5 Uses and Compounds

C. fragile is used for skincare and antiaging products. It is reported to be a regenerating and anti-free radical ingredient, and have rebalancing and energizing properties. Its wealth of macro-elements gives it a remineralizing property [109]. One seller claims that C. fragile is the ideal ingredient to boost tired and mature skin. It is also used as food in eastern Asia and Chile [107, 108, 110, 4]. This species have also antioxidant [111, 112], antibacterial [112, 113, 114, 115], anti-inflammatory [116] immunostimulating [117], antitumor [118], antiangiogenic [119], and antifouling [115] properties. The bioremediation potential of C. fragile has been tested on integrated multitrophic aquaculture (IMTA) [118].

3.2.13 Codium tomentosum Stackhouse

3.2.13.1 Common Names

Spongeweed, Velvet horn.

3.2.13.2 Description

A small green alga (up to $30\mathrm{cm}$ long) with a dichotomously branched, cylindrical frond (Fig. 6.5). The frond is solid and spongy with a felt-like touch and has many colorless hairs which can be seen when the plant is immersed in water. The holdfast is disk-like and formed from many fine threads. C. tomentosum can be confused with C. fragile. However, C. tomentosum tends to have a  more slender frond with rounded tips whereas C. fragile has pointed tips to the frond [1, 120, 121].

Fig. 6.5

Underwater photo of Codium tomentosum

3.2.13.3 Habitat

Mainly on rock in the lower shore.

3.2.13.4 Distribution

C. tomentosum is native to the northeast Atlantic Ocean from the British Isles southward to the Azores and Cape Verde. It has also been recorded around the coasts of Africa and in various other parts of the world.

3.2.13.5 Uses and Compounds

C. tomentosum is used in products from the United States, Germany, France, Italy, and the UK. Some of these products are repair and restoration moisturizers, hydration serums, leg and body creams, muds and butters, bath and shower creams, day creams, night creams, eye creams, antiaging creams, masks, scrubs, lip balms, and lotions. C. tomentosum is a popular food in some parts of Asia [120, 122].

This species have antihelminthic and antiprotozoal [122, 123, 32], antioxidant [124, 125], antigenotoxic [124], antitumor [126], anticoagulant [127, 128, 129], antibacterial [102, 130, 131, 96] activity.

3.2.14 Halimeda opuntia (Linnaeus) J.V. Lamouroux

3.2.14.1 Description

Thick, profusely branched clumps of rounded three-lobed or ribbed leaf-like segments, between $10$ and $25\mathrm{cm}$ in height. The branches are numerous and are in different planes, rather than nearly in a  single plane as some other species are. This alga can cover larger areas with a dense mat so that individual plants are indistinguishable [132, 32].

3.2.14.2 Habitat

Grow in shallow depressions, cracks and crevices, between hard corals and other somewhat protected areas of the reef, down to $55\mathrm{m}$.

3.2.14.3 Distribution

Mediterranean; Caribbean; SW Pacific and Pacific Islands; Japan; Indian Ocean.

3.2.14.4 Uses and Compounds

H. opuntia show hair-growth-stimulating [133], antimicrobial and cytotoxic [134, 135, 136, 137, 138], antioxidant and hepatoprotective [139, 140, 141], larvicidal [142], antileishmanial [143], and antiviral [144] activity.

3.2.15 Halimeda tuna (J. Ellis & Solander) J.V. Lamouroux

3.2.15.1 Description

Thallus calcified, dark green, distinctly segmented with initial branching in one plane; segments disk-like to triangular, up to $2\mathrm{cm}$ wide. Internodal siphons uncalcified, united in twos or threes, and terminating in pseudodichotomous laterals. Surface cells oppressed to one another in a honeycomb pattern, $25$–$75\mathrm{\mu }\mathrm{m}$ in diameter [32].

3.2.15.2 Habitat

Found on hard rocky substratum in shallow water, less than $2\mathrm{m}$ depth.

3.2.15.3 Distribution

Globally in warmer seas: NE Atlantic (Morocco, Azores, Canary Islands); Mediterranean; Caribbean; NW Pacific (Japan); SE Pacific (Chile); SW Pacific; Pacific Islands; Indian Ocean; Australia.

3.2.15.4 Uses and Compounds

This species have antibacterial [114, 145, 146], antioxidant [147, 65], anticoagulant [128], pesticide [136, 148], antifungal [62], Antitrypanosomal [149], cytotoxic and antiproliferative [150] activity.

• Class: Dasycladophyceae

• Order: Dasycladales

3.2.16 Acetabularia acetabulum (Linnaeus) P.C. Silva

3.2.16.1 Description

Thallus with a slender stipe, whitish gray or gray-green, merging into a flattened, funnel-shaped cap at the top; this is divided into $20$–$80$ radial rays, navelled, and annulated around navel and below the cap (Fig. 6.6). During growth, delicate filamentous, forking branchlets arise from the uppermost ring and the stipe. These are discarded soon and are therefore lacking in the mature thallus. Only basal parts perennial, plants with fully developed caps between May and August in the Mediterranean [151, 32].

Fig. 6.6

Underwater photo of Acetabularia acetabulum

3.2.16.2 Habitat

Mostly forming dense stands on rocks and stones in sheltered bays.

3.2.16.3 Distribution

NE Atlantic; Mediterranean; Indian Ocean.

3.2.16.4 Uses and Compounds

For a time, important researches object in cell biology (cell differentiation, interaction of nucleus and cytoplasm)[32].

• Class: Siphonocladophyceae

• Order: Siphonocladales

3.2.17 Valonia utricularis (Roth) C. Agardh

3.2.17.1 Description

Thallus, translucent light- to dark green, primarily consisting of a large (up to $5\mathrm{mm}$ thick and $20\mathrm{mm}$ long) bladder- or club- to hose-like cell, branching at the base rhizoidally (Fig. 6.7). Later due to outgrowths of this cell cylindrical-clavate branches, often contorted and almost gapless densely packed, thus forming intertwined erect stands [152, 32].

Fig. 6.7

Valonia utricularis specimen

3.2.17.2 Habitat

Plants sessile; at times forming extensive stands beneath other algae. Mostly on rock and reef edges in sheltered locations and shallow water, in up to $2\mathrm{m}$ depth.

3.2.17.3 Distribution

Warm NE Atlantic (Portugal to Canary Islands); Mediterranean; Caribbean; Indian Ocean; NW Pacific (Japan, China); Indo-Pacific (Philippines, Vietnam); Pacific Islands; Australia.

3.2.17.4 Uses and Compounds

Show antifungal, antiviral, cytotoxic and atimitotic [62] activity.

• Class: Ulvophyceae

• Order: Cladophorales

3.2.18 Anadyomene stellata (Wulfen) C. Agardh

3.2.18.1 Description

A. stellata consists of erect, bright green, delicate blades with ruffled edges forming densely packed clumps; blades one cell thick, to $10\mathrm{cm}$ in height, formed by veins of filaments radiating from base in fan-like branching pattern. Cells between veins arranged in parallel rows. Margins smoothly rounded, formed by small spherical cells; similar to A. saldanhae which has cells between veins in random arrangement. Also similar to A. lacerata which has lacerated margins formed by elongated vein cells [32].

3.2.18.2 Habitat

Commonly found on rocks or other firm surfaces in the lower intertidal zone.

3.2.18.3 Distribution

Warmer parts of the NE Atlantic (Azores, Canary Islands), Mediterranean; Caribbean; Indian Ocean; W Pacific (Philippines, Indonesia); Australia.

3.2.18.4 Uses and Compound

Have anticoagulant [153], and antifungal [62] activity.

3.2.19 Chaetomorpha aerea (Dillwyn) Kützing

3.2.19.1 Description

Light green filaments, $10\mathrm{cm}$ long, growing attached to the substrate, and mostly grouped in tufts. Filament unbranched, growing in flocks or communities attached to sand covered or bare rocky substratum, $2$–$3\mathrm{cm}$ in height, yellowish green in color. Cells cylindrical, apical cells $111.2$–$111.5\mathrm{\mu }\mathrm{m}$ in length and $110.5$–$111.6\mathrm{\mu }\mathrm{m}$ in breadth, middle cells $54.5$–$62.2\mathrm{\mu }\mathrm{m}$ in length and $88.8$–$89.2\mathrm{\mu }\mathrm{m}$ in breadth, basal cell much longer than the middle and the upper one, showing its length $133.32$–$144.5\mathrm{\mu }\mathrm{m}$ and breadth $55.50$–$58.8\mathrm{\mu }\mathrm{m}$, sheath $17$–$22.5\mathrm{\mu }\mathrm{m}$ in thickness, sometimes lamellate in mature portion [154].

3.2.19.2 Habitat

Ephemeral species, found in intertidal environment, in both exposed and sheltered stations.

3.2.19.3 Distribution

Diffused in Mediterranean, Black Sea, NE Atlantic (from Scandinavia to Portugal) NW Atlantic.

3.2.19.4 Uses and Compounds

Show antibacterial [155, 156, 157] activity.

3.2.20 Chaetomorpha capillaris (Kützing) Børgesen

3.2.20.1 Description

Thallus medium green, loose-lying in shade on tidal flats, forming loose, woolly, entangled masses with few if any attachment cells. Filaments unbranched, of similar diameter throughout. Cells ($70-$) $85$–$100$ $(-105)\mathrm{\mu }\text{m}$ in diameter and L/B $1$–$2$, not collapsing on drying; walls $8$–$12\mathrm{\mu }\mathrm{m}$ thick; chloroplasts densely reticulate with numerous pyrenoids [158].

3.2.20.2 Habitat

In shade on mangrove pneumatophores or under Samphires on tidal flats.

3.2.20.3 Distribution

Mediterranean and North Atlantic; Southern Australia and New Zealand.

3.2.20.4 Uses and Compounds

Have antifungal activity [62].

3.2.21 Chaetomorpha linum (O.F. Müller) Kützing

3.2.21.1 Common Name

Spaghetti algae.

3.2.21.2 Description

Delicate green seaweed, it grows as a filamentous loosely entangled mass (Fig. 6.8). Plants mostly free floating, sometimes attached to rocks and shells; plant body filamentous, less than $20\mathrm{cm}$ long, bright green to yellowish green in color, filaments wiry and stiff, unbranched; cell walls thick, appear jointed or articulated with dark green bands; cells constricted at the transverse walls [159, 160].

Fig. 6.8

Chaetomorpha linum specimens

3.2.21.3 Habitat

Is an intertidal and supralittoral species that can be found in groups of hundreds or thousands of individuals in sandy areas, on rocks or around tide pools.

3.2.21.4 Distribution

Widespread, including Northern Europe to North Africa Atlantic coasts, North and Baltic; Mediterranean; North American Atlantic Coast (Labrador to Florida); NE Pacific (Alaska to California); SE Pacific (Chile); Indian Ocean, China, Japan, Australia, New Zealand.

3.2.21.5 Uses and Compounds

Spaghetti algae, though not palatable to many herbivorous species, is popular in reef aquariums for its ability to remove nitrates, assist in buffering pH, uptake carbon dioxide producing oxygen, and assist in balancing trace elements. It also provides hiding spaces for small creatures [159]. Possible use on biofuel production [161, 162, 163], liquid fertilizer [164], bioremediation in aquaculture [165], and animal feed [166]. Extracts of this species have insecticidal [167], antimicrobial [168, 169, 170, 171], antioxidant [111, 170], larvicidal [171], and antiviral [172] activity.

3.2.22 Cladophora coelothrix Kützing

3.2.22.1 Description

Thallus medium to dark green, drying brownish, forming dense turfs or cushions to several cm across and to $4\mathrm{cm}$ high, composed of a basal tangle of branched, often curved, stolon-like filaments giving rise to ascending, more-or-less erect, branch-systems. Growth largely by divisions of conspicuous apical cells, but intercalary cells may divide into shorter cells; feebly to distinctly acropetal at the apices, densely and irregularly branched with many cells (especially lower ones but often also those near the apices) producing a descending rhizoid from their basal poles, and which attach to the substrate or other filaments with a terminal coralloid holdfast; lateral branches mostly wide-angled (${45}^{\circ }$ or more) arising singly (occasionally two) at or just below a cross wall, with the new wall remaining steeply inclined to the parent cell [173].

3.2.22.2 Habitat

Common in shaded areas or pools near low tide level on rough-water coasts but extending into sheltered areas.

3.2.22.3 Distribution

Warm temperate to tropical Atlantic coasts of Europe, Africa and America; probably widespread in tropical and warm temperate waters, and in southern Australia.

3.2.22.4 Uses and Compounds

Have antimicrobial [174], and antifungal activity [62].

3.2.23 Cladophora fracta (O.F. Müller ex Vahl) Kützing

3.2.23.1 Description

Filaments branched; attached by rhizoids, pale green, up to $80\mathrm{cm}$ long, branching irregular or pseudodichotomously divided at wide angles, cells mostly cylindrical; chloroplast parietal net-like with several pyrenoids; main axis up to $85\mathrm{\mu }\mathrm{m}$ wide, bearing numerous side branches of different lengths; cells of side branches $17$–$38\mathrm{\mu }\mathrm{m}$ wide, $5$ to $17$ times longer than wide, apical cells cylindrical to slightly conical, $16$–$27\mathrm{\mu }\mathrm{m}$ wide, $3.5$ to $25$ times longer than wide [175].

3.2.23.2 Habitat

Frequent in shallow, nutrient-rich ponds and ditches as well as penetrating slightly brackish-water habitats; mostly free floating or unattached and lose lying.

3.2.23.3 Distribution

NE Atlantic (Sweden to Spain); NW Atlantic; Mediterranean; Australia.

3.2.23.4 Uses and Compounds

Have antihypertensive [176], antimycobacterial [177], antioxidant [178], antibacterial [179, 180], antialgal [179], piscidal [179] activity, and possible use for biodiesel production [181, 182].

3.2.24 Cladophora glomerata (Linnaeus) Kützing

3.2.24.1 Description

Plants were up to $20\mathrm{cm}$ high and light to dark green in color. The texture of thallus was soft and slightly mucilage. Plants usually formed in dense tufts well branched. Rhizoids were primary and adventitious and descend from the bases of thallus or from the lower segments of the fronds. Primary branches fused together or not and branched in dichotomous manner. The old branches in the lower portion of the thallus were slight constricted articulations ($80$–$150\mathrm{\mu }\mathrm{m}$ in width and $160$–$900\mathrm{\mu }\mathrm{m}$ in length) and usually branched in dichotomous manner. The branches in the upper portion of thallus were cylindrical ($60$–$120\mathrm{\mu }\mathrm{m}$ in width and $100$–$600\mathrm{\mu }\mathrm{m}$ in length) and branched in dichotomous or trichotomous manner [183].

3.2.24.2 Habitat

Growth of C. glomerata usually requires hard substrates for attachment, such as rocks, mussels, and artificial reef structures.

3.2.24.3 Distribution

Distributed widely around world; NE Atlantic (Sweden to Portugal); NW Atlantic (Canada to Cuba and Mexico); SW Atlantic (Brazil); Mediterranean; Indian Ocean, Pacific.

3.2.24.4 Uses and Compounds

Used on the treatment of burns [184], biosorption of heavy metals [185], animal feed [186], biodiesel production [187], wastewater treatment [188], and as food [189]. Have antibacterial [190, 191, 192], antiprotozoal [193], antioxidant [190, 194], and antifungal activity [192, 195].

3.2.25 Cladophora pellucida (Hudson) Kützing

3.2.25.1 Description

Filaments rigid, erect, setaceous, full dark green, di-tri-chotomous; the axils very acute, the branches erect; articulations many times longer than broad; dissepiments only at the forking of the branches and ramuli [196].

3.2.25.2 Habitat

On the bottoms and sides of deep rock pools, between tide marks, generally near low-water mark.

3.2.25.3 Distribution

NE Atlantic (from Ireland and Britain to Morocco); Mediterranean; SW Atlantic (Brazil); NE Atlantic (South Africa); Indian Ocean (India); Australia.

3.2.25.4 Uses and Compounds

Have antitumor [197] activity.

3.2.26 Cladophora prolifera (Roth) Kützing

3.2.26.1 Description

Unattached or basally attached coarse filaments those are usually less than $0.5\mathrm{mm}$ wide and $3$–$5\mathrm{cm}$ long. The filaments are formed of a single row of often swollen cells; if attached then by a discoid base or by rhizoidal outgrowths [198].

3.2.26.2 Habitat

Grow fixed to rocks in the upper sublittoral zone.

3.2.26.3 Distribution

NE and E Atlantic (from Ireland and Britain to Senegal); Mediterranean; NW and SW Atlantic; SE Atlantic; Indo-Pacific Oceans; Australia.

3.2.26.4 Uses and Compounds

Used on experimental co-culture [199]. Have antimicrobial [200, 201, 202, 203, 96], antifungal [200, 204], antiviral [103], antioxidant [205, 65], and anticoagulant [206] activity.

3.2.27 Cladophora rupestris (Linnaeus) Kützing

3.2.27.1 Description

C. rupestris is a densely tufted plant, darkgreen, which grows up to $20\mathrm{cm}$ in height, with dark green or bluish colored dull fronds. Typical specimens branch profusely upward from the base, in an irregular, whorled or opposite pattern. The stoutness, density, and arrangement of branches give the seaweed a coarse feel (Fig. 6.9).

Fig. 6.9

Herbarium specimen of Cladophora rupestris (MACOI no. 2419)

The morphology of the species is fairly constant over a wide range of habitat conditions and over a wide geographical area. Its morphology is affected by physical damage due to grazing by animals and loss of the apical region on reproduction; both instances are followed by regeneration and proliferation of branches. C. rupestris sometimes forms an almost complete cover of stunted growth at high tide level and occasionally in the splash zone where pools are brackish. Filaments are short and branching dense in the most wave exposed locations [1, 32].

3.2.27.2 Habitat

On solid substratum, in all littoral zones, prefers sandy locations in the lower littoral, tolerant to reduced salt content of seawater.

3.2.27.3 Distribution

NE Atlantic (Scandinavia to N Africa), North Sea and Baltic; Mediterranean; NW Atlantic; NW Pacific (Japan) and SW Pacific; Subarctic.

3.2.27.4 Uses and Compounds

Contains arabinose, carotenoids, galactose, glucose, polysaccharides, protein, rhamnose, sulfuric acid, and xylose [207, 208]. Used for animal feed [209], and ${\mathrm{CO}}_2$ bioremediation [210]. Have antimicrobial [130, 211], antimycobacterial [212], antiprotozoal [212], cytotoxic [212], and antifouling [213] activity.

• Order: Ulvales

3.2.28 Ulva clathrata (Roth) C. Agardh

3.2.28.1 Synonyms

Enteromorpha ramulosa (Smith) Carmichael, Enteromorpha clathrata (Roth) Greville.

3.2.28.2 Common Name

Aonori.

3.2.28.3 Description

Plants less than $30\mathrm{cm}$ long and soft; thallus repeatedly branched in all directions, cylindrical or compressed with narrow branchlets as much as $40\mathrm{cm}$ long, light green in color, plants grow first attached to the substratum but later become free floating; cells of the thallus more or less quadrangular in shape with a single cup-shaped chloroplast; pyrenoids $3$ to $4$.

This species forms tufts, bright green, composed of branched axes, which can reach several centimeters long ($20$–$30\mathrm{cm}$). The main axis and branches are covered with conical branchlets very characteristic [1].

3.2.28.4 Habitat

In rocks and stones, from mid-littoral to sublittoral.

3.2.28.5 Distribution

Entire Atlantic, Mediterranean, Caribbean (Cuba, Mexico), NE and NW Pacific, Australia and New Zealand.

3.2.28.6 Uses and Compounds

Used as biofilter on shrimp (Litopenaeus vannamei) aquaculture [214], on shrimp feed [215, 216], and for human food [217, 4]. Have antibacterial [218, 219, 220, 96], anticoagulant [221], antifungal [217], antiprotozoal [123, 218], larvicidal [222], analgesic [218], anticancer and antiviral [217, 218] activity.

3.2.29 Ulva compressa Linnaeus

3.2.29.1 Synonym

Enteromorpha compressa (Linnaeus) Nees.

3.2.29.2 Common Names

Green nori, Plat darmwier.

3.2.29.3 Description

U. compressa is a green seaweed that can have one of two different growth forms. The first is a flat, narrow sheet with ruffled edges, and the second form (often referred to as Enteromorpha compressa) is a  hollow tube of tissue, rounded at the top. In both forms the sheets of tissue are very thin; in fact they are exactly one cell thick. Several blades or tubes arise from a common attachment point and can grow up to $200\mathrm{mm}$ long. U. compressa is a shallow water species and is often found in tide pools or on rocks in the intertidal and shallow infra-littoral up to $3\mathrm{m}$ deep. As a common tide-pool species, U. compressa is able to withstand great swings in salinity, temperature, and pH [223, 224].

3.2.29.4 Habitat

Marine and estuarine species, rock pools and sandy rocks, particularly in places with widely varying salinities such as upper-shore species.

3.2.29.5 Distribution

U. compressa is widely distributed, found commonly on the NE Atlantic coasts, Pacific coast of North America, throughout the Mediterranean, and also in Africa and Australia.

3.2.29.6 Uses and Compounds

U. compressa, in the same family as sea lettuce is a commonly eaten as a sea vegetable, used fresh or dried for both human and animal consumption for its high nutrient levels and good taste; is used dried in cooking, particularly with eggs [109, 223, 224]. This seaweed is also utilized as fertilizer to introduce a wide range of minerals to the soil. Many benefits have been associated with U. compressa consumption such as cytotoxic [225], antimicrobial [171, 224, 226, 227, 228, 229, 230, 96], antiviral [224], and antioxidant [224, 225, 231, 232, 233, 234] properties. Extracts of U. compressa are also added to cosmetics products for a soothing quality that reduces skin itchiness and tautness [224].

3.2.30 Ulva fasciata Delile

3.2.30.1 Description

Thalli thin, sheet-like, up to $50\mathrm{cm}$ long, consisting of wide blades, $10$ – $15\mathrm{cm}$ wide at base, tapering upward to less that $2.5\mathrm{cm}$ wide at tip. Basally broadened, but the upper portions divided deeply into many ribbon like segments; margins smooth, often undulate. Holdfast is small without dark rhizoids. Bright grass-green to dark green, gold at margins when reproductive, may be colorless when stressed [235, 32].

3.2.30.2 Habitat

U. fasciata is a common species in the intertidal to shallow infra-littoral, often found in tide pools. This species is a quick colonizer and is able to grow very quickly in the right conditions, often reaching bloom levels in the presence of nutrient run-off and fresh water input [236].

3.2.30.3 Distribution

U. fasciata has a worldwide distribution in temperate and tropical waters: NE Atlantic; Mediterranean; Caribbean; West coast South Africa; SW Atlantic; entire Pacific; Indiana Ocean; Australia, New Zealand.

3.2.30.4 Uses and Compounds

U. fasciata is a popular edible seaweed in many areas where it grows, such as Hawaii where it is known as limu palahalala. U. fasciata has a very fine texture and lovely fresh taste and is often chopped into salads or used as a relish, though it can also be cooked and used in soups [236]. Green algae extracts are also very nutrient rich and are a wonderful addition to natural cosmetic products. Have antiviral [237, 238], algicidal [239, 240] antifungal [241] larvicidal [242], cytotoxic [242], antifouling [243], antibacterial [241, 242, 244, 245, 246, 247], antioxidant [246] activity.

3.2.31 Ulva intestinalis Linnaeus

3.2.31.1 Synonym

Enteromorpha intestinalis (Linnaeus) Nees.

3.2.31.2 Common Name

Gut weed.

3.2.31.3 Description

U. intestinalis is a conspicuous bright grass-green seaweed, consisting of inflated irregularly constricted, tubular fronds that grow from a small discoid base (Fig. 6.10). Fronds are typically unbranched. They may be $10$–$30\mathrm{cm}$ or more in length and $6$–$18\mathrm{mm}$ in diameter, the tips of which are usually rounded. Like other members of the genus, U. intestinalis is a summer annual, decaying and forming masses of bleached white fronds toward the end of the season [1, 32].

Fig. 6.10

Ulva intestinalis specimens

3.2.31.4 Habitat

In sheltered as well as exposed locations, on boulders, breakwaters and piers, in pools, also epiphytically; from the upper littoral (also supra-littoral) pools into the sublittoral.

3.2.31.5 Distribution

More or less globally distributed: entire Atlantic, Mediterranean, Caribbean, NE and NW Pacific, Indian Ocean, Australasia, Antarctica.

3.2.31.6 Uses and Compounds

This species is used as human food [4] and animal feed [248, 249], for biomonitoring of heavy metals [250, 251], have antimicrobial [252, 253, 86, 96], antifungal [252], antitumor [254, 255], antihemolytic [253], larvicidal [256], antifouling [257], antiplasmodial [258], antiprotozoal [259], algicidal [260], and antioxidant [261, 262, 263] activity.

3.2.32 Ulva lactuca Linnaeus

3.2.32.1 Common Names

Sea lettuce, Green laver.

3.2.32.2 Description

U. lactuca is commonly called sea lettuce. Its color can range from light yellowish green to darker green, but is most commonly a vivid green underwater. When exposed at low tide or when washed up on a beach, it is typically darker green. Out of the water the seaweed looks like a rather slimy lime-green mass but in the water the alga actually does look very much like young lettuce leaves. U. lactuca is vivid green and cellophane thin (only two cell layers thick), and forms light yellowish green to dark-green translucent sheets. The soft frond grows as a single, irregular, but somewhat round-shaped blade with slightly ruffled edges which are often torn. There can be numerous small holes or perforations scattered throughout. The frond is connected to rocks with a small, almost invisible discoid holdfast, and does not have a stipe. U. lactuca may grow to a diameter of $20$–$30$ cm, although it is frequently much smaller, with larger sheets feeling slightly thicker than smaller specimens [1, 264, 32].

3.2.32.3 Habitat

From the tidal zone to the sublittoral, often free floating in pools.

3.2.32.4 Distribution

U. lactuca is ubiquitous, common to most shorelines around the world.

3.2.32.5 Uses and Compounds

U. lactuca is available in different forms from companies in countries which include the UK, Ireland, France, Germany, Vietnam, China, Canada, and the United States. It is sold both in fresh and dried form, in flakes, powders, and salad mixes. It is a delicate seaweed with a mild flavor. U. lactuca is sometimes eaten as green laver, but it is considered inferior to purple laver. It is used as a seasoning by itself and in blends, and can be found in soups and salads [32]. This species is also used in animal feed [265]. It also a key ingredient in many cosmetic and personal care items such as soap, lotion, toner, lifting cream, eye cream, lip cream, makeup remover, body polish, bath soaks, antiaging products, shaving lotion, shampoo, conditioner, and serums [264, 266]. It is also a component in gardening and fertilizer products [3].

This species have antioxidant [267, 268], antibacterial [115, 145, 171, 228, 269, 270, 271, 70, 72], antitumor [126, 72], anti-inflammatory [272], antifouling [115, 273], antifungal [115, 72], antiviral [263, 72], antialgal [115] activity.

3.2.33 Ulva linza Linnaeus

3.2.33.1 Synonym

Enteromorpha linza (Linnaeus) J. Agardh.

3.2.33.2 Common Names

Breed darmwier, Bright grass kelp, Welded green nori.

3.2.33.3 Description

U. linza is a large, ribbon-like species of green seaweed that may reach up to $30\mathrm{cm}$ in length. The thalli are unbranched and often have a frilled margin. The thalli taper into a distinct stipe below and are highly compressed. The width of the thallus is greater in the middle than at the base and may reach $5\mathrm{cm}$ in width. U. linza is bright light to dark green in coloration [274, 32].

3.2.33.4 Habitat

Usually found on rocks or in rock pools, usually marine but occasionally found under brackish conditions.

3.2.33.5 Distribution

U. linza is found worldwide in bays and sheltered coasts.

3.2.33.6 Uses and Compounds

U. linza is used as an edible seaweed in many cultures for its high nutrient content and silky texture. Green algae extracts are also very nutrient rich and make a beneficial addition to natural cosmetic products [274]. Have antibacterial [228, 269, 275, 276, 60, 96], anti-inflammatory [277], and antiviral [278].

3.2.34 Ulva prolifera O.F. Müller

3.2.34.1 Synonym

Enteromorpha prolifera (O.F. Müller) J. Agardh

3.2.34.2 Common Name

Green ribbon plant.

3.2.34.3 Description

The fronds are tubular, though often more or less flattened, little to much branched. The arrangement of the cells, in longitudinal and transverse rows in the central part of the frond, is characteristic of this species, as are the cylindrical chloroplasts seeming to fill the cell and the usually single, central pyrenoids [279].

3.2.34.4 Habitat

A common green alga near the top of the shore, on rocks or other algae, on open coasts or in estuaries and harbors, where it may grow mixed with U. intestinalis or other species of the same genus.

3.2.34.5 Distribution

NE Atlantic (Britain to Senegal); Atlantic Islands, Mediterranean; NW and W Atlantic; Caribbean; SE Atlantic; Pacific; China, Australia.

3.2.34.6 Uses and Compounds

Used for food [280] and animal feed [281, 282]; potential use for the production of biofuels [283]. Have also antibacterial [171, 284], antifouling [285], antioxidant [101], antifungal [226, 286], antitumor [126], immunomodulatory [287] activity.

3.2.35 Ulva rigida C. Agardh

3.2.35.1 Common Name

Green laver.

3.2.35.2 Description

U. rigida is a bright green seaweed with a variety of growth forms. The two cell layer thick, sheet-like blades can grow as tiny blades forming carpet-like turfs, or as clumps of several larger blades, or solitarily. In its largest form, Ulva rigida can reach up to $10\mathrm{cm}$ in height, but size and blade shape are both highly variable. Blades may be flat or ruffled, sometimes bearing many small holes (perforations) and sometimes not. However, the defining characteristics of U. rigida are common among all its growth forms: the two cell layers of the blades are easily separable, like a deflated balloon, and the holdfasts are composed of many small, tough, dark rhizhoids that are absent in other Ulva species. U. rigida is common in intertidal and shallow sublittoral waters, often found in tidepools. This seaweed is able to withstand high variation in salinity and water chemistry and actually seems to prefer areas with freshwater input [288, 32].

3.2.35.3 Habitat

Epilithic, in the entire littoral zone to the sublittoral.

3.2.35.4 Distribution

U. rigida has a worldwide distribution in temperate and warm seas.

3.2.35.5 Uses and Compounds

U. rigida is often utilized as a fresh sea vegetable by many island cultures for its high nutrient content and fresh taste [288, 289]. This species is used to for animal feed [290, 291].

Green algae extracts are also very nutrient-rich and make a beneficial addition to natural cosmetic products. The polysaccharide ulvan is easily extracted from U. rigida. It is composed of β-($1$,$4$)-xyloglucan, glucuronan, and cellulose in a linear arrangement. It corresponds to a water-soluble dietary fiber and is resistant to both human digestive tract enzymes and degradation by colonic bacteria. This polysaccharide cannot therefore be considered prebiotic; however, it could potentially be hydrolyzed to bioactive oligosaccharides [288, 292].

U. rigida have antigenotoxicity [293, 294], anti-hyperglycemic [293], immunomodulating [295], antibacterial [201, 296, 297, 298, 299, 300], antioxidant [300, 301, 302], antileishmanial [303] activity.

3.2.36 Ulvaria obscura (Kutzing) Gayral

3.2.36.1 Synonym

Monostroma obscurum (Kützing) J. Agardh

3.2.36.2 Description

Thallus widely bladed, similar to that of Ulva, turning brown on dying; monostromatic blade; occurring not often; bipolar species [304].

3.2.36.3 Habitat

In sublittoral, at $3$–$17\mathrm{m}$ depth.

3.2.36.4 Distribution

NE Atlantic (Iceland and Norway to Portugal); Atlantic Islands; NW Atlantic (Alaska and Greenland to Washington); SW Atlantic (Argentina).

3.2.36.5 Uses and Compounds

Ulvaria obscura produces a dopamine that functions as antiherbivore defense [305, 306], and flavonoids with protective effect action against free radicals, protecting collagen surrounding of blood vessels. This species have antioxidant [307] activity.

• Order: Ulotrichales

3.2.37 Gayralia oxysperma (Kützing) K.L. Vinogradova

3.2.37.1 Synonym

Monostroma oxyspermum (Kützing) Doty

3.2.37.2 Description

Thalli forming leafy monostromatic blades from a few centimeter to a meter or more in length. Cells in the upper portion of blade polygonal and isodiametric, becoming more elongate toward base with long rhizoidal projections in holdfast region. In surface view, cells in groups of two or four; cells uninucleate with parietal chloroplast and single prominent pyrenoid traversed by thylakoids [308, 32].

3.2.37.3 Habitat

On rocks, boulders or on other seaweeds, older free floating; common through the entire littoral to sublittoral boundary, preferably in sheltered sites; tolerant to changing salinity.

3.2.37.4 Distribution

European coastlines (Atlantic, North Sea and Baltic); Atlantic coasts of North, Central and South America; Caribbean; East Pacific coastlines (Alaska to California), Japan, Mauritius, S Australia.

3.2.37.5 Uses and Compounds

Consumed as green vegetable (SE Asia, China) and used for animal feed [109, 32]. Have antiviral activity [309].

3.3 Domain/Empire Eukaryota, Kingdom Plantae, Phylum Rhodophyta (Red Algae)

• Class: Bangiophyceae

• Order: Bangiales

3.3.1 Bangia fuscopurpurea (Dillwyn) Lyngbye

3.3.1.1 Description

Gelatinous, unbranched, blackish-purple filaments, at first uniseriate later multiseriate, attached by rhizoidal outgrowths from basal and adjacent cells; cells with central star-shaped rhodoplast with pyrenoid [310].

3.3.1.2 Habitat

On rocks, wood, etc., as fleecy mat, especially at high tide level on exposed coasts in autumn and winter, disappearing in spring or early summer, at other times present as sparse filaments.

3.3.1.3 Distribution

NE Atlantic (Iceland to Senegal)); W Atlantic (Brazil and Argentina); Caribbean; W Pacific (Japan, China); NE Pacific (California, Mexico); Indo-Pacific/Indian Ocean; Australia.

3.3.1.4 Uses and Compounds

Consumed as vegetable [310]. Have antioxidant, antibacterial, antiviral, cytotoxic [205, 311] activity.

3.3.2 Porphyra leucosticta Thuret

3.3.2.1 Synonym

Pyropia leucosticta (Thuret) Neefus & J. Brodie

3.3.2.2 Description

Delicate membranous monostromatic reddish-brown fronds, becoming pink on drying, to $150\mathrm{mm}$ long, with very short stipe from basal holdfast [1, 2, 312].

3.3.2.3 Habitat

Usually epiphytic on larger algae, littoral to shallow sublittoral, spring to autumn, widely distributed, common.

3.3.2.4 Distribution

NE Atlantic (Norway to Portugal); Mediterranean; NW Atlantic (Canada and USA); SW Atlantic (Brazil); SE Atlantic (Angola).

3.3.2.5 Uses and Compounds

Produces high percentage of vitamin C and natural carotenoids, and therefore P. leucosticta could become a valuable source of raw material to obtain such compounds, which have multiple uses in the pharmaceutical field, cosmetic and food industry [313]; used for food [3, 314], and for IMTA aquaculture [315]. Extracts have high antioxidant [316], and low antiprotozoal, antimycobacterial, and cytotoxic [317] activity.

3.3.3 Porphyra linearis Greville

3.3.3.1 Description

Delicate, linear, membranous, purple-brown fronds, $20$–$40\mathrm{mm}$ $(-200)\mathrm{mm}$ long and $5$–$10$ $(-25)\mathrm{mm}$ broad, usually simple with short stipe from basal holdfast; orange patches when reproductive [1, 318].

3.3.3.2 Habitat

Marine species, zone forming on rock in the upper intertidal and splash zone of semiexposed and exposed shores, generally distributed; a winter and spring annual appearing on semiexposed and exposed.

3.3.3.3 Distribution

Recorded throughout Northern Europe, from Norway to Portugal, Azores. Canada (Labrador) to USA (at least Connecticut).

3.3.3.4 Uses and Compounds

Used for food [3, 319, 320, 4], and for aquaculture [321, 322, 323]. Extracts have antimicrobial activity [130].

3.3.4 Porphyra umbilicalis (Linnaeus) Kützing

3.3.4.1 Common Names

Purple laver, Pink laver, Laver, Nori.

3.3.4.2 Description

A red alga (up to $40\mathrm{cm}$ across) with a circular (P. umbilicalis) or irregularly shaped (P. leucosticta), broad frond that is membranous but tough (Fig. 6.11). The plant attaches to rock via a minute discoid hold-fast, is greenish when young gradually changes into purplish red, and has a polythene-like texture. Another species is the P. linearis, with narrow stem that attaches the base and appears mainly in winter [1, 324, 325].

Fig. 6.11

Herbarium specimen of Porphyra umbilicalis (MACOI no. 110)

3.3.4.3 Habitat

On rocks, mussels, etc., in the littoral to splash zone, generally distributed, abundant, especially on exposed coasts.

3.3.4.4 Distribution

P. umbilicalis occurs in the North Atlantic. In the east, it is found in Iceland and has been recorded from Norway to Portugal and in the Western Mediterranean. In the West, P. umbilicalis is found from Labrador in Canada to the mid-Atlantic coast of the United States.

3.3.4.5 Uses and Compounds

P. umbilicalis is rich in protein, vitamins A, C, E, and B, and trace minerals, and also rich in omega-3 polyunsaturated fatty acids (GlossaryTerm

EPA

and GlossaryTerm

DHA

). It contains special compounds named mycosporine-like amino acids (GlossaryTerm

MAA

s) which are valuable in certain types of personal care products. Some of the favorable properties associated with compounds from P. umbilicalis are that it [3, 324, 325]: acts as a natural bio-protector against UVA-induced damage; prevents the formation of sun burn cells and premature photo-aging; protects cell structures, especially membrane lipids and GlossaryTerm

DNA

from damage by GlossaryTerm

UV

-induced radicals; helps in the re-equalization of lipid deficient skins; increases epidermal hydration; protects against Trans Epidermal Water Loss; improves intercellular cohesion; reinforces the skin barrier function; restores cell membrane structure after irritant damage; has oxygenating properties that helps revitalize stressed and fatigued skin; able to diminish the appearance of fine lines and wrinkles.

As a result, it is used in many different product applications, such as [325, 326]: antioxidant; daily GlossaryTerm

UV

protective skin care, sun care; anti-photo-aging care; cares for dry, reactive and sensitive skins; lip care; after sun care.

Specific products identified so far from France, Ireland, Italy, Spain, and United States utilizing P. umbilicalis include regenerating face creams and antiaging facial creams, facial masks, and aftershave balm. For food, it is sold in flaked and whole leaf form, as a nori substitute, as laver, and is used as an ingredient in several snack mixes and condiments. It is also used as a pet nutrition supplement [3, 320, 325, 4].

• Class: Florideophyceae

• Order: Ahnfeltiales

3.3.5 Ahnfeltia plicata (Hudson) E.M. Fries

3.3.5.1 Description

Perennial red seaweed which forms dense, tangled tufts (Fig. 6.12). The fronds are very fine, tough, and wiry with irregular or dichotomous branching and up to $21\mathrm{cm}$ in length. The holdfast is disk-like or encrusting, $0.5$–$2\mathrm{cm}$ in diameter. The fronds are dark brown when moist and appear almost black when dry. The uppermost branches are often green [327].

Fig. 6.12

Ahnfeltia plicata specimens

3.3.5.2 Habitat

On rocks, mid-littoral to sublittoral, especially common on sand-covered rocks, widely distributed, common.

3.3.5.3 Distribution

N and NE Atlantic (Greenland to Azores); SW Atlantic (Uruguay); NE Pacific (Alaska to Mexico); NW Pacific (Russia); SE Pacific (Chile); Indian Ocean; Antarctica and the Sub-Antarctic Islands.

3.3.5.4 Uses and Compounds

A source of so-called Russian Agar (agar of high quality and low sulfate content) [32, 328, 329]. A. plicata is one of the major seaweeds harvested for commercial colloid production as it produces a very high quality, low sulfate and used for many purposes. It forms a major component of Asian cooking, often showing up in soups and jellies. As a nonanimal derived thickening agent, A. plicata is also widely used for vegan products (such as marshmallows, gummy bears, cosmetics, etc.) in place of gelatin [330].

• Order: Bonnemaisoniales

3.3.6 Asparagopsis armata Harvey

3.3.6.1 Common Names

Harpoon weed, Harpoon-alga.

3.3.6.2 Description

Thallus of the gametophyte tufted, main axes cylindrical, denuded at the base, densely tufted apically, tufts with pyramidal outline, forming lateral brush-like tassels; some lateral branches develop into unbranched, elongated-pointed harpoon-like anchoring structures covered with barbed hooks (a characteristic feature of the species) which are usually pinnately arranged (Fig. 6.13). The tetrasporophyte (Falkenbergia phase) is small, almost spherical tufts (similar to cotton balls) of multiseriate branching threads (microscope required) [32].

Fig. 6.13

Underwater photo of Asparagopsis armata

3.3.6.3 Habitat

Both phases readily reproduce vegetatively. Drift specimens of gametophyte readily attach to other algae by barbed branchlets, and produce new shoots; introduced from Southern Hemisphere [331].

3.3.6.4 Distribution

A. armata is native to the Southern Hemisphere (Australia and New Zealand) but has been introduced to the Northern Hemisphere, first recorded in Europe in 1925 and since spreading throughout the Channel Islands and all around Great Britain. A. armata is now found globally, from the Canary Islands to Morocco and throughout the Pacific and Indian Oceans [32, 331].

3.3.6.5 Uses and Compounds

A. armata extract is a powerful antioxidant with antibacterial qualities and is a valued ingredient in many cosmetic products. Present strong cytotoxicity against human cancer cell lines [316, 332, 62]. A. armata is also harvested or grown for the production of phycocolloid [333, 334].

The species has also been examined for its potential as a source of pharmaceutical and bioactive agents since its extracts contain anti-Leishmania [335], antioxidant [336], antiviral [337, 338], antifungal [62], antimicrobial [336, 339, 340, 62] compounds.

3.3.7 Asparagopsis taxiformis (Delile) Trevisan de Saint-Léon

3.3.7.1 Common Name

Cat’s tail red seaweed.

3.3.7.2 Description

Thallus fluffy, fine, filamentous creeping mats or tufts, to $4\mathrm{cm}$ high, pale red to gray-pink; branching irregular to alternate. Branches cylindrical, occasionally moniliform (with segments swollen or bead-like), $30$–$80\mathrm{\mu }\mathrm{m}$ diameter, central axial filament surrounded by $3$ pericentral cells; cells commonly pointed at tips, twice as long as broad, each set rotated approximately ${60}^{\circ }$; apex with single prominent apical cell cutting off lens-shaped cell basally; holdfast initially disk-like, later becoming branched, tangled, creeping, forming filamentous mass. Tetrasporangia solitary on outer filaments, not in groups or series, formed from one pericentral cell of segment. Fluffy appearance and shaped like a Christmas tree. Grows $3$–$15\mathrm{cm}$ high [32, 341].

3.3.7.3 Habitat

A tropical/subtropical species; thalli are epilithic; in shallow sublittoral habitats with heavy water motion.

3.3.7.4 Distribution

Globally distributed in tropical and subtropical seas: E Atlantic (Azores, Madeira, Canary Islands, W Africa, Cape Verde Islands to Nigeria); W Atlantic (Brazil); Caribbean; W Pacific (Japan, China); NE Pacific (California, Mexico); Pacific Islands (Hawaii); Indo-Pacific/Indian Ocean; Australia, New Zealand.

3.3.7.5 Uses and Compounds

The species has been examined for its potential as a source of pharmaceutical and bioactive agents since its extracts contain antifouling and anticyanobacterial [342], antifungal [341], anticoagulant [343], and antimicrobial [341, 344, 345] compounds.

Used fresh in Hawaii as limu kohu (generic name for seaweed) to flavor meat and fish dishes [341, 346].

3.3.8 Bonnemaisonia hamifera Hariot

3.3.8.1 Common Names

Bonnemaison’s Hook Weed; Pink cotton wool.

3.3.8.2 Description

Gametophyte plants occurring from March–June, brownish red, fronds feathery, with a slightly flattened axis to $1\mathrm{mm}$ wide and $350\mathrm{mm}$ long, attached to Cytstoseira and other algae by crosier-shaped, hook-like modified branches. Tetrasporophyte (Trailliella phase) plants occurring all year round, but most obvious in October–March, brownish red, much branched, filamentous, in dense cotton-wool-like tufts to $25\mathrm{mm}$ in diameter [347].

3.3.8.3 Habitat

Probably introduced from Japan at the end of the last century; gametophyte first found in Europe (Isle of Wight) in 1893, on rocks and other algae, lowest littoral and sublittoral.

3.3.8.4 Distribution

NE Atlantic (Scandinavia to Canary Islands); SE Atlantic (South Africa); Mediterranean; NW Pacific (Russia, Japan); NE Pacific (California, Mexico).

3.3.8.5 Uses and Compounds

Extracts of this species have antibacterial [348, 349], antioxidant [350], and antihypertension [351] activity.

• Order: Ceramiales

3.3.9 Alsidium helminthochorton (Schwendimann) Kützing

3.3.9.1 Common Name

Corsican moss.

3.3.9.2 Description

Upright radially organized polysiphonous thalli, up to $15\mathrm{cm}$ high, with cylindrical axes and progressively narrower distal branches. Branch apices abruptly tapering; trichoblasts spirally arranged on axis, present on every segment but soon deciduous; parenchymatous cortication occurs to near branch apex $6$–$8$ pericentral cells. Lateral polysiphonous branches originate from trichoblast basal cell [352].

3.3.9.3 Habitat

Found on calm, shallow, photophilic biotopes.

3.3.9.4 Distribution

Mediterranean.

3.3.9.5 Uses and Compounds

In Mediterranean, the Greek physician, Stephanopoli, discovered in 1775 that the red seaweed Alsidium helminthochorton, found on the rocky shores of Corsica, have an efficient anthelmintic action [353, 354, 355].

3.3.10 Boergeseniella thuyoides (Harvey) Kylin

3.3.10.1 Description

Cylindrical, cartilaginous, tufted, deep brownish-purple fronds, to $150\mathrm{mm}$ high, from creeping rhizoidal base; fronds distichously bi-tripinnate, patent, short, of nearly uniform length giving branches a linear appearance; ramuli short, spinelike; polysiphonous, central siphon with $8$–$12$ pericentral siphons and outer cortication of small, colored cells; articulations as broad as long, barely visible [356].

3.3.10.2 Habitat

On rock and epiphytic in shallow, wave-exposed pools in lower intertidal.

3.3.10.3 Distribution

NE Atlantic (Ireland and Britain to Morocco).

3.3.10.4 Uses and Compounds

Extracts of this species have antiviral [337, 357], and antibacterial [358] activity.

3.3.11 Bornetia secundiflora (J. Agardh) Thuret

3.3.11.1 Description

B. secundiflora is dark red in color, firm and rigid when fresh. The thallus is $5$–$20\mathrm{cm}$ high when erect, fan shaped with blunt tips (apices), much branched and tufted, with branches often curved over. The plant has a jelly-like texture. Branches are sparse at the base becoming denser toward the apices [359].

3.3.11.2 Habitat

B. secundiflora grows on boulders and bedrock, often under overhangs, from just below extreme low water to $3\mathrm{m}$ depth. It tolerates sand on rocks and moderately to extreme wave exposure.

3.3.11.3 Distribution

NE Atlantic (England to the Canary Islands, W Africa); Mediterranean.

3.3.11.4 Uses and Compounds

Extracts have antifouling activity [360, 361].

3.3.12 Bostrychia scorpioides (Hudson) Montagne

3.3.12.1 Description

Frond flexuous, dull purple, filiform, much branched, inarticulate, dotted, subdichotomous; the branches three or four times pinnated; pinnae and pinnulee patent; apices strongly rolled inward [362].

3.3.12.2 Habitat

On muddy shores near high-water mark, on lower stems of saltmarsh flowering plants, widely distributed, locally abundant.

3.3.12.3 Distribution

Atlantic shores of Europe, from England to Spain.

3.3.12.4 Uses and Compounds

Produces Sorbitol; the polyol sorbitol is known to occur naturally in the Rosaceae family especially in Sorbus aucupria and in the algae, e. g., Bostrychia scorpioides. It is used in the pharmaceutical industry for the treatment against constipation and it known to stimulate vascular contraction as well. Its use in the cosmetics industry, especially in the manufacture of toothpaste is an example of a well established use of carbohydrate and its derivatives in this sector [363].

3.3.13 Brongniartella byssoides (Goodenough & Woodward) F. Schmitz

3.3.13.1 Description

Soft, tufted, deep purplish red fronds, to $300\mathrm{mm}$ long; main axis well-defined, bi- or tripinnate, bearing alternate, distichous branches. Branches and branchlets articulated, with central siphon and $5$–$7$ pericentral siphons, clothed with short, slender, repeatedly dichotomously branched, monosiphonous ramuli. Its color is light red brown to almost black when dry [32, 364].

3.3.13.2 Habitat

On stones and shells and epiphytic, lower littoral and sublittoral, spring and summer, generally distributed, common in NE Atlantic.

3.3.13.3 Distribution

NE Atlantic (Scandinavia to Portugal, North Sea, E Baltic Sea), Mediterranean Sea.

3.3.13.4 Uses and Compounds

Great antioxidant potential; strong cytotoxicity against human cancer cell lines [316].

3.3.14 Ceramium virgatum Roth

3.3.14.1 Synonym

Ceramium rubrum C. Agardh.

3.3.14.2 Common Names

Hornweed, Red hornweed.

3.3.14.3 Description

Small red seaweed growing up to $30\mathrm{cm}$ tall. It has a filamentous frond that is irregularly and dichotomously branched, with the branches narrowing toward pincer-like tips. The holdfast is a minute conical disk that extends into a dense mass of rhizoidal filaments. The plant is reddish brown to purple in color and has a banded appearance when viewed closely [1, 365].

3.3.14.4 Habitat

C. virgatum is both epilithic and epiphytic, often growing on the stipes and fronds of Fucus spp., Mastocarpus stellatus, and Laminaria hyperborea as well as on the leaves of Zostera marina.

3.3.14.5 Distribution

C. virgatum is common worldwide from the Americas to Europe (Atlantic), through the Mediterranean, down to South Africa, Asia, and Antarctica.

3.3.14.6 Uses and Compounds

C. virgatum is used as an extract for cosmetic products [313, 366], produces an agar-type polysaccharide [367], and have antiviral [368], antibacterial [276, 369, 370, 371], antioxidant [372], antialgal [373], antiprotozoal, antimycobacterial and cytotoxic activity [317].

3.3.15 Chondria capillaris (Hudson) M.J. Wynne

3.3.15.1 Synonym

Chondria tenuisssima (Withering) C. Agardh

3.3.15.2 Description

Thallus bushy, vivid purple to pale yellowish red, upright cylindrical main axes cartilaginous-firm, with numerous long, softer irregularly spirally arranged lateral axes, branching to the fourth degree; the recent branches also stand rather loosely, spindle-shaped tapering at both ends, the apices pointed and crowned by hair-thin filamentous tufts (magnifying glass required); plants with reproductive bodies appear more densely branched peripherally; discoid holdfast, on prostate axes additional rhizoids [32].

3.3.15.3 Habitat

On rocks, pebbles, and shells, in shallow water at wave-protected sites, at depths to about $6\mathrm{m}$.

3.3.15.4 Distribution

NE and E Atlantic, Mediterranean, Caribbean, Indian Ocean (India, East Africa, Mauritius).

3.3.15.5 Uses and Compounds

Extracts have antioxidant and vermifuge [335] activity.

3.3.16 Chondria coerulescens (J. Agardh) Falkenberg

3.3.16.1 Description

C. coerulescens has bluish or yellowish fronds with blue iridescence (Fig. 6.14). The fronds are flexible and cartilaginous in texture, turning black when dry. Young axes show a striking turquoise iridescence when alive; the thalli consist of cylindrical erect axes or trailing tufts, and is $3$–$8\mathrm{cm}$ high when erect. The distinct main axis is $0.4$–$0.5\mathrm{mm}$ in diameter, branching sparsely at irregular intervals in a  spiral pattern to $1$–$3$ orders of branching. Branches are linear, often long and curve downward gradually tapering to a slender point, and reattach by secondary holdfast. The morphology shows relatively little variation except that some thalli consist only of inconspicuous isolated erect axes whereas others form dense tufts [1, 374].

Fig. 6.14

C. coerulescens specimen (note the blue iridescence in water)

3.3.16.2 Habitat

C. coerulescens is a sublittoral species, growing on pebbles in mud from extreme low water to $4\mathrm{m}$ depth.

3.3.16.3 Distribution

NE Atlantic (Ireland and Britain to Senegal); Mediterranean.

3.3.16.4 Uses and Compounds

Produces hemagglutinins [375].

3.3.17 Chondria dasyphylla (Woodward) C. Agardh

3.3.17.1 Description

The thallus is $10$–$21\mathrm{cm}$ high, reddish brown in color, with the primary erect axis initially arising from a discoid holdfast to $4\mathrm{mm}$ diameter, subsequently further erect axes arising from the same holdfast giving a clumped appearance. Short creeping branchlets are produced from the lowermost parts of erect axes, and become attached to the substrate by small rhizoidal haptera about $0.5\mathrm{mm}$ diameter. The thallus branching is irregularly radial, erect-patent with 3–4 orders of branching, ultimate branches arising every two to six (eight) axial cells. Ultimate branchlets are $250$–$500\mathrm{\mu }\mathrm{m}$ diameter, the variation being a reflection of the robustness of the plant [376].

3.3.17.2 Habitat

Usually found in mid-littoral pools.

3.3.17.3 Distribution

NE Atlantic (Ireland to W Africa); Mediterranean, Caribbean, Indian Ocean.

3.3.17.4 Uses and Compounds

According to the results of Khanavi etal study [377], hexane fraction of Chondria dasyphylla could contain phytosterols (fucosterol) with cytotoxicity against breast and colon cancer cell line. Extracts of this seaweed have larvicidal [378], antibacterial, antifungal, antiprotozoal, antiviral, antifertility, and hypoglycemic [218] activity.

3.3.18 Cryptopleura ramosa (Hudson) L. Newton

3.3.18.1 Description

A short thallus with a stout midrib arises from a discoid holdfast, widening as it branches into flattened red-brown or red-purple fronds to a height of $20\mathrm{cm}$ (Fig. 6.15). The fronds are thin and membranous, around $2.5\mathrm{cm}$ in width and may have a slight blue iridescence under water. Repeated branching gives it a bushy tangled appearance with the branches tapering to rounded tips. Morphology is variable and blades can be either erect or prostrate and broadly wedged or strap shaped. Margins may be smooth, undulating, and denticulate or hooked, frequently with a blue iridescence underwater [379].

Fig. 6.15

Underwater photo of C. ramosa

3.3.18.2 Habitat

On rocks and often as epiphyte on stipes of L. hyperborea, lower intertidal and sublittoral, generally distributed, common.

3.3.18.3 Distribution

NE Atlantic (Scandinavia to Canary Islands); SW Atlantic (Brazil, Uruguay), Mediterranean Sea.

3.3.18.4 Uses and Compounds

Tested for biodiesel production [380]. Have antifouling [373], antiviral [381], algicidal [382], and antifouling [361] activity.

3.3.19 Dasya rigidula (Kützing) Ardissone

3.3.19.1 Description

Present irregular subdichotomous branching; variable cortication among the thallus; ocellate apex; and stichidia with four tetrasporangia per segment. Traditionally, the species of this genus are diagnosed depending on the branching pattern, presence of ocellate apex, and degree of cortication [383, 384].

3.3.19.2 Habitat

From the mid-littoral to deep waters.

3.3.19.3 Distribution

NE and E Atlantic (From France to Senegal); Atlantic Islands; West Atlantic; Caribbean; SW Atlantic (Brazil); Mediterranean.

3.3.19.4 Uses and Compounds

Have antibacterial activity [60].

3.3.20 Delesseria sanguinea (Hudson) J.V. Lamouroux

3.3.20.1 Common Name

Sea beech

3.3.20.2 Description

Membranous, bright crimson fronds, with cartilaginous, cylindrical, branched stipe, from thickened discoid holdfast, to $300\mathrm{mm}$ long (Fig. 6.16). Branches bearing spirally arranged, leaflike, ovate-lanceolate blades, each with short stipe and pinnately branched midrib, membranous portion monostromatic, margin undulate (on mature blades), entire; reproductive structures in small oval, stalked blades, borne on midribs in winter [385].

Fig. 6.16

Herbarium specimen of Delesseria sanguinea (MACOI no. 2549)

3.3.20.3 Habitat

On rocks, in deep shady lower intertidal pools and in the sublittoral.

3.3.20.4 Distribution

NE Atlantic (Scandinavia to Portugal, North Sea, Baltic Sea); Mediterranean (sporadically).

3.3.20.5 Uses and Compounds

D. sanguinea is used in the cosmetics industry for its anticoagulant properties and vitamin K content; the active principle being termed Delesserine [386, 387]. Have also anti-inflammatory and antiskin aging [387, 388, 389] activity.

3.3.21 Digenea simplex (Wulfen) C. Agardh

3.3.21.1 Description

Cylindrical axes ($1\mathrm{mm}$ in diameter) rigid, with short secondary branches of the same diameter, carrying dense tufts of thin, straight ramuli; $5$–$25\mathrm{cm}$. Cartilaginous at the apices. Light red (the naked base) to dark red (the branches). The gametophyte and the sporophyte are similar [390].

3.3.21.2 Habitat

Found year round in photophyle sheltered biotopes, from surface down to a few meters; frequently covered by epiphytes.

3.3.21.3 Distribution

Worldwide distribution in tropical and temperate waters: Mediterranean (with the exception of the Lion Gulf), tropical Atlantic, Red Sea, and Indo-Pacific.

3.3.21.4 Uses and Compounds

The active agent (Kainic acid), originally isolated in Japan from this species, but now manufactured commercially [32], has antihelminthic activity. The extracts from these red algae have antifungal [204] activity.

3.3.22 Halopithys incurva (Hudson) Batters

3.3.22.1 Description

Tough, cylindrical, cartilaginous, shaggy, dark red fronds, $250\mathrm{mm}$ long. Main branches alternate or subdichomous, simple or pectinate in lower parts, much branched above, often curved and hooked. Branches with usually double row of short, pointed ramuli on the upper side, ramuli straight, curved or hooked, slightly narrowed at base; axis of $1$ central, $5$ pericentral siphons, with several layers of cortical cells, outermost small, colored; articulations visible, shorter than broad [32].

3.3.22.2 Habitat

On rocks, mid-littoral pools to subtidal.

3.3.22.3 Distribution

Warmer NE Atlantic (Ireland to Canary Island); Mediterranean.

3.3.22.4 Uses and Compounds

Have antibacterial [358, 391, 392], antioxidant [393], antitumor [394], and antiviral [357] activity.

3.3.23 Heterosiphonia plumosa (J. Ellis) Batters

3.3.23.1 Description

H. plumosa is a red to deep crimson seaweed which appears black when dried. This species has a flattened, fern-like appearance with a hairy thallus growing from a discoid holdfast. The fronds are flat or slightly cylindrical up to $20\mathrm{cm}$ in length and $0.5\mathrm{cm}$ in diameter at the base, tapering toward the apex. The primary branching from the main frond occurs in a single plane, and is alternately, yet irregularly spaced with up to $1\mathrm{cm}$ between each branch. Each branch is bare at the base, with the rest bearing an irregular and alternately arranged series of smaller secondary branches. The secondary branches are progressively shorter toward the apex, and each branch bears numerous pointed branchlets giving an overall tufted and feather-like appearance [395].

3.3.23.2 Habitat

On rocks and epiphytic, low intertidal pools and sublittoral, southern and western shores, common in the south, rare in the north.

3.3.23.3 Distribution

NE Atlantic (Scandinavia to Portugal).

3.3.23.4 Uses and Compounds

Have high antioxidant activity [316].

3.3.24 Hypoglossum hypoglossoides (Stackhouse) F.S. Collins & Hervey

3.3.24.1 Description

Membranous, rose-pink fronds, $20$–$200$ $\left(300\right)\mathrm{mm}$ long, arising from a discoid base. Frond linear-lanceolate, with well-marked midrib and thin membranous margins, $1$–$5$ $\left(8\right)\mathrm{mm}$ wide, repeatedly branched irregularly from midrib; fronds with pointed apices, margins without microscopic veins, monostromatic except in midribs [396].

3.3.24.2 Habitat

On rocks and epiphytic, lower intertidal and sublittoral to $30\mathrm{m}$, most abundant in L. hyperborea forests.

3.3.24.3 Distribution

NE and E Atlantic (Scandinavia to Portugal, Azores, Canary Islands, Cap Verde Islands); NW and W Atlantic (North Carolina to West Indies): Mediterranean.

3.3.24.4 Uses and Compounds

Have antimicrobial activity [397].

3.3.25 Laurencia microcladia Kützing

3.3.25.1 Description

Thallus erect, flexible, soft texture, forming dense tufts up to $15\mathrm{cm}$ in length. The thallus has greenish-yellow and pinkish apices easily visible. Flaccid consistency does not adhere completely to the herbarium sheet when dry; thalli fully cylindrical with $385$–$410\mathrm{\mu }\mathrm{m}$ in diameter; branching irregularly, alternating, dense in the upper two-thirds of the plant, to three branching orders. Adhered to the substrate by rhizoids, from which emerge branches ending in small secondary locking disks [398].

3.3.25.2 Habitat

Present in the mid-littoral rock bottom and up to $1$–$2$ feet deep in the sublittoral exposed coasts. Often found in very beaten but has also been collected in puddles of lower mid-littoral and sublittoral.

3.3.25.3 Distribution

NE Atlantic (from France to Mauritania); Atlantic Islands (Azores, Canary Islands); Mediterranean; NW Atlantic (USA); Caribbean; SW Atlantic (Venezuela, Brazil).

3.3.25.4 Uses and Compounds

Have antimitotic and cytotoxic, [399, 400, 401, 402, 403, 62], antiparasitic [402, 404, 405], and antifungal [62] activity.

3.3.26 Laurencia obtusa (Hudson) J.V. Lamouroux

3.3.26.1 Description

Plants $1.5$–$2.5\mathrm{cm}$ tall, bushy, with green or yellow axes and rose branchlets, main stems long, which are sparingly alternately branched, $0.75$–$1.50\mathrm{cm}$, but above are increasingly closely paniculately branched and spreading, the smallest branches and the short, truncate, ultimate branchlets opposite or subverticillate, $0.5$–$0.75\mathrm{mm}$ diameter; tetrasporangia in a band below the apex of the hardly modified branchlets [406].

3.3.26.2 Habitat

On solid substrata, in extremely shallow locations in calm shallow water, also in exposed locations within the intertidal zone.

3.3.26.3 Distribution

Worldwide in warm temperate to tropical seas.

3.3.26.4 Uses and Compounds

Have antibacterial [32, 407, 408, 409, 410], antimalarial [411, 412], antitumor [316, 413, 414], antioxidant [316, 410, 415], and antifouling [416] activity.

3.3.27 Laurencia pyramidalis Bory de Saint-Vincent ex Kützing

3.3.27.1 Description

Globose tufts of brittle, cartilaginous, narrow, cylindrical, reddish brown to yellowish-red fronds, $150\mathrm{mm}$ long, from small discoid base (Fig. 6.17). Axis simple, branches patent, often opposite, spirally arranged, shorter toward apex giving regular pyramidal outline [417].

Fig. 6.17

Underwater photo of Laurencia pyramidalis

3.3.27.2 Habitat

Usually epiphytic, annual, lower intertidal.

3.3.27.3 Distribution

NE Atlantic (From Ireland and Britain to Portugal); NW Mediterranean.

3.3.27.4 Uses and Compounds

Have antioxidant and antimicrobial activity [410].

3.3.28 Laurencia viridis Gil-Rodríguez & Haroun

3.3.28.1 Description

Thallus annual, cartilaginous, mainly greenish with pink tips, with erect axes averaging $4$–$8\mathrm{cm}$ (range $2$–$15\mathrm{cm}$) long, having alternate or helicoid branching only in the upper two-third of the thallus; ovoid spermatangia produced in cup-shaped receptacles; cystocarps urceolate, and sessile; tetrasporangia in parallel abaxial rows [418].

3.3.28.2 Habitat

Mainly restricted to exposed low intertidal sites, growing on rocks with strong wave action.

3.3.28.3 Distribution

Macaronesian region (Azores, Madeira, Selvages, Canaries, and Cape Verde).

3.3.28.4 Uses and Compounds

Have cytotoxic and antitumor [419, 420, 421, 422, 423] activity.

3.3.29 Nitophyllum punctatum (Stackhouse) Greville

3.3.29.1 Description

Delicately membranous, rose-pink fronds with an elongate fan-shaped outline, margins distinctly frilly, to $40\mathrm{mm}$ or, exceptionally, to $1\mathrm{m}$, sessile or shortly stipitate ($<2\mathrm{mm}$ long); frond veinless, undivided or deeply subdichotomously divided to the base; apices blunt or rounded, often ribbon-like (Fig. 6.18). Gametophyte plants form rounded spots to $5\mathrm{mm}$ in diameter whilst tetrasporophyte plants form characteristically elongated spots [424].

Fig. 6.18

Underwater photo of N. punctatum

3.3.29.2 Habitat

In littoral pools in winter and early spring and in the sublittoral ($15\mathrm{m}$) on cobble or other mobile surfaces and on bedrock in the lower parts of kelp forests from spring to summer.

3.3.29.3 Distribution

NE Atlantic (Norway to Canary Islands); NW Atlantic (N America); Caribbean, Mediterranean and Indian Ocean (India, Egypt); Sub-Antarctic.

3.3.29.4 Uses and Compounds

Potential bio-insecticides against mosquito larvae [66].

3.3.30 Osmundea hybrida (A.P. de Candolle) K.W. Nam

3.3.30.1 Description

Cylindrical, cartilaginous, tufted, dark purple to greenish-yellow fronds, $150\mathrm{mm}$ long; main axis with repeatedly pinnate branching, branches mostly alternate, shorter toward apex giving pyramidal outline; ultimate ramuli short, patent, truncate; axis monosiphonus with elongated pericentral cells and $1$–$2$ outer layers of rounded colored cells; apex concave, with ephemerally colorless dichotomous hairs surrounding apical cell [425].

3.3.30.2 Habitat

On stones and shells, sometimes epiphytic, upper intertidal, widely distributed, locally common.

3.3.30.3 Distribution

NE Atlantic (Britain to Morocco); SW Atlantic (Brazil).

3.3.30.4 Uses and Compounds

Perform antibacterial activity [340, 391].

3.3.31 Osmundea pinnatifida (Hudson) Stackhouse

3.3.31.1 Common Name

Pepper dulse.

3.3.31.2 Description

A small red alga (up to $8\mathrm{cm}$ in length), it is tough and cartilaginous with flattened fronds (Fig. 6.19). Branching is alternate and occurs in one plane only, with branches becoming shorter toward their apex and broadly rounded. The plant is highly variable in size and coloration depending upon its location on the shore. Higher shore plants are generally dwarfed and yellow green in color, owing to exposure to high levels of sunshine while on the lower shore they are reddish brown [1, 426].

Fig. 6.19

Osmundea pinnatifida specimen

3.3.31.3 Habitat

On rocks, perennial, throughout intertidal, often as flattened rosettes covering exposed rocks, also sublittoral, generally distributed, abundant.

3.3.31.4 Distribution

NE Atlantic (Ireland and Britain to Senegal); Atlantic Islands; SW Atlantic (Brazil); Mediterranean (Turkey); SW and East Asia, North America, South America, Australia, and New Zealand.

3.3.31.5 Uses and Compounds

The marine polyether triterpenoid dehydrothyrsiferol $298$, originally isolated from the red alga Laurencia pinnatifida was shown to induce apoptosis in estrogen-dependent and independent breast cancer cells [419, 420]. Have antibacterial [27, 358, 427, 428], antioxidant [234, 429], antileishmanial [430, 431], anticancer [225, 432], antifouling [257, 275], insecticidal, and antifungal [226] activity.

This aromatic seaweed is dried and used as a pepper- or curry-flavored spice in Scotland, Ireland, and Portugal (Azores Islands) [3, 426].

3.3.32 Osmundea truncata (Kützing) K.W. Nam & Maggs

3.3.32.1 Description

O. truncata is much less common than O. pinnatifida, is more pinnately branched, generally grows epiphytically, and rapidly degenerates on collection [433].

3.3.32.2 Habitat

On rocks, perennial, throughout intertidal, often as flattened rosettes covering exposed rocks.

3.3.32.3 Distribution

Mediterranean.

3.3.32.4 Uses and Compounds

Extracts have antimicrobial activity [130].

3.3.33 Pterosiphonia complanata (Clemente) Falkenberg

3.3.33.1 Description

Thallus with prostate and erect axes, the erect ones flat-compressed and with distichous, alternate pinnate branching (Fig. 6.20); brownish-red color, flexible, and cartilaginous texture; attached by rhizoids which form discoid adhesive structures [434].

Fig. 6.20

Pterosiphonia complanata specimen

3.3.33.2 Habitat

On rocks and as epiphyte on other algae, in the entire intertidal zone and below.

3.3.33.3 Distribution

Warm to tropical regions of the Atlantic and Mediterranean.

3.3.33.4 Uses and Compounds

Extracts have antiviral [357], and antibacterial [358, 435] activity.

3.3.34 Ptilota serrata Kützing

3.3.34.1 Synonym

Ptilota pectinata (Gunnerus) Kjellman

3.3.34.2 Description

P. serrata is a typically dark red and less than $5\mathrm{cm}$ tall seaweed. It is branched in opposite pairs, often with wavy spandrels protruding from the ends of the branches. Simple branchelets with serrated margins on one side stand opposite to composite-pinnately divided lateral branches on the other [32].

3.3.34.3 Habitat

Understory alga in the shallow sublittoral becoming dominant beyond $10\mathrm{m}$.

3.3.34.4 Distribution

North Atlantic (Greenland, Svalbard, Faroe Islands, Norway), and N Pacific (Alaska to Washington).

3.3.34.5 Uses and Compounds

Has hemagglutinating activity [375].

3.3.35 Rhodomela confervoides (Hudson) P.C. Silva

3.3.35.1 Description

Cylindrical, cartilaginous, bushy, brownish-red fronds, to $300\mathrm{mm}$ long. Much branched, repeatedly, irregularly. Branches clothed with small, pinnate branchlets and simple, pointed ramuli. In winter, branchlets are shed and frond appears bare, spiky, and very different from summer appearance. Central siphon surrounded by elongated cells with the outer band of small colored cells, articulations not visible [436].

3.3.35.2 Habitat

On rocks and shells, intertidal pools at all levels; widely distributed, common.

3.3.35.3 Distribution

Warmer NE Atlantic (Ireland to Canary Islands); Mediterranean.

3.3.35.4 Uses and Compounds

Extracts have antibacterial [437], antifungal [438], antihyperglycemic [439], cytotoxic [440], and antioxidant [441, 442, 443] activity.

3.3.36 Rytiphlaea tinctoria (Clemente) C. Agardh

3.3.36.1 Description

Thallus red, very dark, cartilaginous, abundantly branched, formed on the principal axes, flattened branches alternate provided in turn with short ramuli ends more or less curved. Structure–uniaxial quickly becoming complex by recloisonnement; in cross section showing the axial cell medulla sometimes indistinct, surrounded by $5$ pericentral cells; thallus with apical growth [444].

3.3.36.2 Habitat

In the upper sublittoral, occasionally in the mid-littoral.

3.3.36.3 Distribution

NE Atlantic (France to Mauritania); Atlantic Islands; Mediterranean.

3.3.36.4 Uses and Compounds

Extracts are used as colorant [445]. Extracts have antimicrobial activity [130].

3.3.37 Spyridia filamentosa (Wulfen) Harvey

3.3.37.1 Common name

Feathery seaweed.

3.3.37.2 Description

Plants, dull brown to pale pink, usually less than $20\mathrm{cm}$ tall when in low turf mats, up to $18\mathrm{cm}$ tall in areas of good water motion; fastened by small discoid holdfast, the lower portions of plants and the lower branches tending to entangle; one to several erect axes, branching irregularly dichotomous or completely irregular, at times also alternate or unilateral; axes crisp, brittle, branching to $4$–$5$ or more orders, the last orders short, becoming matted and giving plants fuzzy appearance; plants often look whitish or lightly calcified, but calcification from crustose coralline algae or sediment, not inherent in plants [446].

3.3.37.3 Habitat

On solid substrates in calm protected areas or adrift; to $8\mathrm{m}$ deep; common on eroded coral in sandy areas, but occurring in sandy mud as well, in matted intertidal turfs on coral and basalt.

3.3.37.4 Distribution

NE and E Atlantic (from Ireland and Britain to Sierra Leone); Atlantic Islands; NW and W Atlantic (USA, Mexico); Caribbean; SW Atlantic; Indian Ocean; SE Pacific; Australia and New Zealand.

3.3.37.5 Uses and Compounds

Extracts have antibacterial [421, 447, 448, 449, 60], and antitumor [421] activity.

3.3.38 Vertebrata lanosa (Linnaeus) T.A. Christensen

3.3.38.1 Synonym

Polysiphonia lanosa (Linnaeus) Tandy.

3.3.38.2 Common Names

Wrack siphon weed, Many tubed gable weed.

3.3.38.3 Description

V. lanosa is a filamentous red alga that grows as an obligate epiphyte on Ascophyllum nodosum. The short, cylindrical, cartilaginous fronds form beautiful dense reddish purple tufts along the ochre colored thalli of their host. Branches of this alga are dichotomous with pointed tips. Formerly classified as Polysiphonia lanosa, it lacks the distinctive banded pattern typical of Polysiphonia species. As an obligate epiphyte, V. lanosa cannot grow except attached to other seaweed species by tiny structures called rhizoids that grow into the tissue of the algal host. A. nodosum is the most frequent host, though V. lanosa is sometimes found on Fucus species such as F. vesiculosus as well, so it is abundant where these species thrive [450].

3.3.38.4 Habitat

Hemi-parasitic on A. nodosum, more rarely on F. vesiculosus, never on rock (appearances can be deceptive as it can grow on old stalks of both species) in the sheltered mid-littoral, generally distributed, usually abundant where Ascophyllum occurs. Vertebrata is generally infected with a tiny, more or less colorless parasitic red alga called Choreocolax polysiphoniae, to which it is closely related [451].

3.3.38.5 Distribution

V. lanosa is fairly common in the N. Atlantic, along the coasts of North America and Europe.

3.3.38.6 Uses and Compounds

V. lanosa is valued for its strong antioxidant and anticancer properties, used in supplements and health and beauty products [450]. Extracts of this species have cytotoxic [452], antioxidant [453], antibacterial [454], antifungal [455], and antifouling [373, 454] activity.

• Order: Corallinales

3.3.39 Amphiroa beauvoisii J.V. Lamouroux

3.3.39.1 Description

More or less erect, sometimes bushy. Size: $2$–$5\mathrm{cm}$ high. Branching: dichotomous, occasionally irregular. Intergenicula: tapered toward the base and flattened at the apices (up to $3\mathrm{mm}$ long, the lower diameter $0.6$–$0.65\mathrm{mm}$, the upper diameter $0.4\mathrm{mm}$) apices characteristically knife-like and striped. Genicula: with $2$ ($3$–$4$) rows of cells. Color of living specimen: pink, pink-violet. Color of dried specimen: pink-violet to white [456].

3.3.39.2 Habitat

Like that of A. rigida, species of sheltered environments, on sublittoral, from surface to $30\mathrm{m}$ deep.

3.3.39.3 Distribution

Widely distributed in tropical and subtropical seas.

3.3.39.4 Uses and Compounds

Extracts have antibacterial activity [457].

3.3.40 Amphiroa cryptarthrodia Zanardini

3.3.40.1 Description

Thallus erect, bushy; endophytic base on other calcareous algae (particularly on Lithophyllum species). Size: $2$–$4\mathrm{cm}$ high. Dichotomous branching, regular and geometric (angle of about ${90}^{\circ }$); branch junctions usually not coinciding with intergenicula. Branches lying on different planes, slightly swollen apices. Intergenicula cylindrical with rare annular swellings, tapered on the upper part of fronds $1$–$4$ $\left(4.5\right)\mathrm{mm}$ long, $0.25$–$0.6\mathrm{mm}$ in the lower diameter, upper diameter $0.15$–$0.18\mathrm{mm}$. Dark red to pink violet (rare), apart from lighter apices due to annular ridges [458].

3.3.40.2 Habitat

On the rocks in sheltered waters where they often form large lawns, in the same station of A. rigida (but less frequently); also reported in tide pools.

3.3.40.3 Distribution

NE Atlantic (from France to Senegal); Mediterranean.

3.3.40.4 Uses and Compounds

Used on functional foods and pharmaceuticals [205]; extracts have antifungal and antimitotic activity [62].

3.3.41 Amphiroa fragilissima

3.3.41.1 Description

Thalli with dense cushion-like tufted growth, very brittle to strong calcification; branches cylindrical, thin, segmented, rather regularly forking, sometimes also trichotomous, the angles between two fork branches usually rather wide (broadly Y-shaped); the segments are slightly swollen at the endings; yellowish red to whitish pink [32].

3.3.41.2 Habitat

Common in shallow water, especially in sea-grass meadows and rock hollows; to $10\mathrm{m}$ depth.

3.3.41.3 Distribution

Widely distributed in tropical and subtropical seas.

3.3.41.4 Uses and Compounds

Used on functional foods [109], and the extracts have antiviral [237], antibacterial [40], cytotoxic and antioxidant [459], oxytocic and espamogenic [460] activity.

3.3.42 Amphiroa rigida J.V. Lamouroux

3.3.42.1 Common Name

Twig algae.

3.3.42.2 Description

Thallus growth lawn-like, segmented branches terete, brittle (calcified), usually forking and simultaneously laterally branching, narrowing toward the tip, segments distally inconspicuous (Fig. 6.21); purple-like conceptacles mostly numerous, especially on peripheral branches [32].

Fig. 6.21

Amphiroa rigida specimens

3.3.42.3 Habitat

Species recorded in shallow and deep waters in sheltered and shaded sites; sometimes found on rocky pools in exposed areas; mainly on sublittoral.

3.3.42.4 Distribution

Cosmopolitan species, present in warmer and tropical seas.

3.3.42.5 Uses and Compounds

Extracts have antimicrobial [391], antifungal, cytotoxic, and antimitotic [62] activity.

3.3.43 Corallina elongata J. Ellis & Solander

3.3.43.1 Description

Whitish pink to reddish lilac, calcified, articulated fronds, fish-bone-like arrangement, to $50\mathrm{mm}$ high, axis compressed, repeatedly pinnate from discoid base, more abundantly and regularly branched than C. officinalis; articulations small [1].

3.3.43.2 Habitat

On rocks, exposed coasts, lower intertidal, southern and western coasts, occasional.

3.3.43.3 Distribution

NE Atlantic (Ireland and Britain to Senegal); Mediterranean.

3.3.43.4 Uses and Compounds

Used for R-phycoerythrin extraction and for functional foods [461]. Extracts have antimicrobial [228], antifungal and antiviral [62] activity.

3.3.44 Corallina officinalis Linnaeus

3.3.44.1 Common Name

Coral weed.

3.3.44.2 Description

Whitish pink to lilac, calcified, articulated fronds, $60$–$70$ $(-120)\mathrm{mm}$ high, axis cylindrical to compressed, repeatedly pinnate from and expanded discoid base, branching often irregular (Fig. 6.22). Growth form very variable often stunted. In unfavorable habitats erect system vestigial, but extensive base may be present [1].

Fig. 6.22

Underwater photo of C. officinalis

3.3.44.3 Habitat

On rocks, mid-littoral pools and drainage runnels, lower intertidal and shallow sublittoral, widespread and abundant, especially on exposed coasts.

3.3.44.4 Distribution

C. officinalis has been recorded widely in the north Atlantic, from northern Norway to Morocco and from Greenland to Argentina. It is found along the Atlantic coasts of North America from Labrador south to Connecticut and Maryland in the United States. C. officinalis has been reported in Japan, China, Australasia, South Africa, and the Arctic Sea.

3.3.44.5 Uses and Compounds

C. officinalis is a very popular ingredient among cosmetics and health and personal care companies. There are known sellers of C. officinalis-based products in the United States, China, Italy, France, Switzerland, and Germany. These are products for men and women, and include toners, moisturizers, cleansers, emulsions, essences, astringents, eye creams, wash gels, shower gels, shave balm, hydration sprays and creams, and masks [462]. Extracts have antimicrobial [201], anthelmintic [354], and antioxidant [335, 463] activity.

3.3.45 Haliptilon attenuatum (Kützing) Garbary & H.W. Johansen

3.3.45.1 Description

Thallus habit: erect, bushy with dense not entangled fronds (D). Size: $2$–$2.5\mathrm{cm}$ high. Branching: alternate, dichotomic-pinnate (D-A) (whorled); distal dichotomous branchlets. Intergenicula: cylindrical, tapered near apices, $0.2$–$0.4$ $\left(0.5\right)\mathrm{mm}$ long, $0.07$–$0.1\mathrm{mm}$ in diameter. Genicula: $60$–$200\mathrm{\mu }\mathrm{m}$ long. Color of living specimen: from red scarlet to purple. Color of dried specimen: from white to ivory yellow [464].

3.3.45.2 Habitat

Epiphytic species often on H. virgatum; mainly on sublittoral.

3.3.45.3 Distribution

Alboran Sea: Morocco; Middle Western Mediterranean Sea: Italy; North Adriatic Sea: Italy, Croatia.

3.3.45.4 Uses and Compounds

Extract has antibacterial activity [60].

3.3.46 Jania adhaerens J.V. Lamouroux

3.3.46.1 Description

This species is small ($4$–$5\mathrm{mm}$ high), heavily calcified, and forms intricately entwined clumps. The branches are pinkish-red color, regularly dichotomous, terete or slightly compressed, and slightly curve downward. Terminal segments are acuminate. This is an epiphytic species, decumbent on other seaweeds such as the species of Sargassaceae, growing in the sublittoral zones along shorelines moderately exposed to water movement [465].

3.3.46.2 Habitat

Growing in the sublittoral zones along shorelines moderately exposed to water movement.

3.3.46.3 Distribution

Atlantic Islands; Mediterranean; SW and SE Atlantic; Caribbean; Indo-Pacific Oceans; Australia.

3.3.46.4 Uses and Compounds

Extracts have antigenotoxic [466], antifungal, antiviral, and antimicrobial [103, 62] activity.

3.3.47 Jania rubens (Linnaeus) J.V. Lamouroux

3.3.47.1 Description

Slender, rose-pink, articulated, calcified fronds, to $50\mathrm{mm}$ high; repeatedly dichotomously branched, luxuriant specimens secondarily pinnate (Fig. 6.23). Segments cylindrical, to $120\mathrm{\mu }\mathrm{m}$ diameter, those bearing branches somewhat compressed, to $180\mathrm{\mu }\mathrm{m}$ diameter. Fixed by small conical disk, but spreading vegetatively by developing attachment disks from branches in contact with solid substratum [467].

Fig. 6.23

Jania rubens specimens

3.3.47.2 Habitat

Epiphytic, found only growing epiphytically on the brown algae Cladostephus and Cystoseira lower littoral, often abundant.

3.3.47.3 Distribution

The range of J. rubens stretches from the Baltic Sea and Norway in the north to Portugal, Senegal, East Africa, and the Azores in the south; it is also found in the Mediterranean, the Canary Islands, Indian Ocean, Black Sea, and China Sea, as well as around Brazil.

3.3.47.4 Uses and Compounds

J. rubens has recently starting to be used by cosmetic companies as an extract in natural beauty products. It is prized for its ultra-moisturizing and protective properties due to the high concentration of minerals and trace elements present in its tissue. One provider notes that J. rubens is characterized by a concentration of minerals and trace elements $20000$ to $40000$ times greater than that of seawater, thus giving it re-mineralizing properties. It is also used in skin whitening and hydrating products [468].

Extracts of this species have antitumor [126], bio-insecticide [463], antimicrobial [469, 470], antihelmintic and cytotoxic [354, 471], antifouling [472], and antifungal [62] activity.

3.3.48 Jania rubens var. corniculata (Linnaeus) Yendo

3.3.48.1 Description

Thallus erect, bushy, attached by a basal crustose disk. Size: $1$–$4\mathrm{cm}$ high; dichotomous branching, abundant, and entangled branches. Intergenicula: cylindrical, slightly compressed, bearing basal, sometimes articulated projections (horn-like); becoming wider at distal apex, $0.40$–$0.75\mathrm{mm}$ long (times) $0.10\mathrm{mm}$ in diameter. Genicula: irregular filaments $90$–$160\mathrm{\mu }\mathrm{m}$. Color of living specimen: from violet pink more or less intense. Color of dried specimen: white to yellow ivory [473].

3.3.48.2 Habitat

Epilithic or epiphytic on other algae (particularly Cladostephus species), in well-lit sites. Bathymetric

3.3.48.3 Distribution

From surface to shallow waters ($3\mathrm{m}$).

3.3.48.4 Distribution

NE Atlantic (from Ireland and Britain to Morocco); Mediterranean.

3.3.48.5 Uses and Compounds

Extracts have antioxidant and antimicrobial activity [474].

3.3.49 Lithophyllum byssoides (Lamarck) Foslie

3.3.49.1 Synonym

Lithophyllum lichenoides Philippi

3.3.49.2 Description

L. byssoides commonly grows in the intertidal zone. Living specimens, gray–violet in color, form characteristic cushion-like clumps, composed of densely interweaving and anastomosing lamellae which are more or less smooth on the dorsal surface and ridged on the ventral one. Growth form with spiniform lamellae has also been observed. Thalli grow by forming concretions of approximately $10$ to $20$ cushion-like dumps [475].

3.3.49.3 Habitat

It grows on rocky substrata at mid-littoral.

3.3.49.4 Distribution

NE Atlantic (Spain, Portugal to Senegal); Mediterranean (Italy).

3.3.49.5 Uses and Compounds

Extracts have antifungal activity [62].

3.3.50 Lithothamnion corallioides (P.L. Crouan & H.M. Crouan) P.L. Crouan & H.M. Crouan

3.3.50.1 Common Name

Maerl.

3.3.50.2 Description

An unattached, fragile, alga with a calcareous skeleton. It is very similar to and often confused with Phymatolithon calcareum. Its form is very variable but it commonly occurs as highly branched nodules forming a 3D lattice. Individual plants may reach $4$–$5\mathrm{cm}$ across and are bright pink in color when alive but white when dead [476].

3.3.50.3 Habitat

Typically found at less than $20\mathrm{m}$ depth on sand, mud or gravel substrata in areas that are protected from strong wave action but have moderate to high water flow. Usually found as unattached plants.

3.3.50.4 Distribution

NE Atlantic (Norway to Mauritania); Mediterranean.

3.3.50.5 Uses and Compounds

Used as fertilizer and as a constituent of pharmaceutical preparations [477, 478]. Extracts have antifungal activity [62].

3.3.51 Lithothamnion glaciale Kjellman

3.3.51.1 Common name

Knobby coralline-crust algae.

3.3.51.2 Description

Bright pink to purplish, minutely white-speckled calcareous crust, becoming very thick, usually with abundant regular or irregular branches, free or attached to substratum [479].

3.3.51.3 Habitat

On rocks, pebbles, shells or free-living, lower intertidal (north-east coasts) and sublittoral to deeper waters.

3.3.51.4 Distribution

In the NE Atlantic from the British Isles north to Arctic Russia including the Faeroe Isles, Iceland and western Baltic; in the NW Atlantic from Cape Cod north to Arctic Canada and Greenland; also northern Japan and China in the western Pacific.

3.3.51.5 Uses and Compounds

Commercial extraction for use as a soil conditioner on acidic ground, as an animal food additive, for the filtration of acid drinking water and in pharmaceutical and cosmetic products [386, 479]. Extracts promote the induction of metamorphosis of the sea urchin larvae (Strongylocentrotus droebachiensis) [480].

3.3.52 Mesophyllum lichenoides (J. Ellis) M. Lemoine

3.3.52.1 Description

Pale to dark purple thin, brittle, leafy calcified fronds, attached at base, margins free, lobed. Fronds semicircular, concentrically banded (Fig. 6.24). Reproduction takes place in winter and spring in small, wart-like conceptacles [481].

Fig. 6.24

Underwater photo of Mesophyllum lichenoides

3.3.52.2 Habitat

Epiphytic on C. officinalis in mid-littoral pools.

3.3.52.3 Distribution

NE Atlantic (from Ireland to Mauritania); Mediterranean.

3.3.52.4 Uses and Compounds

Used as a soil conditioner on acidic ground [386]. Extracts have antifungal, cytotoxic and antimitotic activity [62].

• Order: Gelidiales

3.3.53 Gelidiella acerosa

3.3.53.1 Description

G. acerosa is a red algae with yellowish brown, tufted, entangled, erect, cylindrical thalli reaching $6\mathrm{cm}$ tall. The ends of the fronds are pinnately divided, giving it a feathered appearance. Branch tips of G. acerosa terminate in a single apical cell. Short, thick branches attached to the substratum by stoloniferous rhizoids form dense mats along shallow reefs. G. acerosa is found on surf-exposed and moderately wave-sheltered rocks and reefs in the lower mid-littoral and the sublittoral zone, and in tide pools at higher levels on the shore [482, 483].

3.3.53.2 Habitat

In tide pools, attached to rock reefs at depth of $0$–$1\mathrm{m}$; in association with Gelidiopsis and Gelidium species.

3.3.53.3 Distribution

Atlantic Islands: Azores and Cape Verde Islands.

3.3.53.4 Uses and Compounds

G. acerosa is an important commercial species for agar production [484, 485, 486, 487]. It has also been used traditionally for the preparation of agar-forming hard jellies, or eaten fresh and also prepared as a salad vegetable or cooked and eaten mixed with rice [4]. However, over recent years, G. acerosa has become a key ingredient in a staggering number of products [109]. It is used in nearly $150$ hair products, including: hair color and bleaching; shampoos and conditioners; styling mousse, foam, gels, sprays, and lotions; hair relaxers and detanglers; antidandruff hair masks [483].

Extracts have antifungal [488], contraceptive [489], antioxidant [490], antifungal, and antibacterial [490, 491, 492, 493] activity.

3.3.54 Gelidiella ramelosa (Kützing) Feldmann & G. Hamel

3.3.54.1 Description

Plants occur as turfs to $1$–$2\mathrm{cm}$ in height, with prostrate stolons attached by clusters of rhizoids to rock. Erect axes are irregularly pinnately branched and terete to slightly compressed. Structurally, the medulla is pseudoparenchymatous with no discernible central axis, and rhizines are absent. Spermatangia occur in surface sori. Tetrasporangia are borne in irregular whorls in terete, basally constricted stichidia that are lateral on erect axes [494].

3.3.54.2 Habitat

Growing as sparse turf amongst coralline algae.

3.3.54.3 Distribution

NE Atlantic (from France to Portugal); Mediterranean; Australia.

3.3.54.4 Uses and Compounds

Extracts have cytotoxic and antimitotic activity [62].

3.3.55 Gelidium corneum (Hudson) J.V. Lamouroux

3.3.55.1 Synonym

Gelidium sesquipedale (Clemente) Thuret.

3.3.55.2 Common Name

Kanteen.

3.3.55.3 Description

Dark red, hard consistency, cartilaginous, and may reach $30\mathrm{cm}$ in length thalli. Branches with obtuse apex and attenuated at the base (Fig. 6.25). This species typically forms dense stands of clumped fronds, often under a kelp canopy [1].

Fig. 6.25

Gelidium corneum specimens

3.3.55.4 Habitat

On rocks and tide pools in exposed areas.

3.3.55.5 Distribution

E Atlantic (Britain to South Africa); W Atlantic (USA to Brazil); Mediterranean; Indo-Pacific zone; Australia.

3.3.55.6 Uses and Compounds

One of the main sources of Agar [495, 496]. Extracts are used for the production of edible films containing carvacrol for ham packages, and other edible films with antimicrobial effect [497, 498, 499, 500]. The antimicrobial and antioxidant activity was demonstrated in several studies [269, 501, 502].

3.3.56 Gelidium pulchellum (Turner) Kützing

3.3.56.1 Description

Cartilaginous, regularly or irregularly bipinnate, dark red-brown fronds, $50$–$100\mathrm{mm}$ high, arise from a creeping base. Main axes narrow, cylindrical, somewhat flattened above. Ultimate branches short, pointed at first, later$\pm$spathulate, particularly when reproductive; appearance variable with Habitat and time of year [503].

3.3.56.2 Habitat

Abundant in and around tidal pools in mid- and lower littoral in high-light situations; generally epiphytic on C. officinalis; widely distributed, common.

3.3.56.3 Distribution

NE Atlantic (Ireland and Britain to Portugal and Morocco). Australia.

3.3.56.4 Uses and Compounds

Source of agar [3, 503, 504]. Extracts have antibacterial [358], and antiviral [357] activity.

3.3.57 Gelidium pusillum (Stackhouse) Le Jolis

3.3.57.1 Description

Cartilaginous, purplish, or blackish red, turf-forming, $2$–$10\mathrm{mm}$ high, arising from extensive creeping base and incorporating shell debris and small mollusks; erect fronds flattened and leaf-like and $0.5$–$2\mathrm{mm}$ broad [505].

3.3.57.2 Habitat

Marine and estuarine species, on rock pools and sandy rocks, particularly in places with widely varying salinities such as upper shore species.

3.3.57.3 Distribution

NE and E Atlantic (from Norway to Benin); Mediterranean; EW Atlantic; Caribbean; SE Atlantic; SW Atlantic; Indian Ocean; SW Pacific.

3.3.57.4 Uses and Compounds

Source of agar [505]. Extracts have antibacterial [358], and antifungal [62] activity.

3.3.58 Gelidium spinosum (S.G. Gmel.) P.C. Silva

3.3.58.1 Description

Small alga, cartilaginous, crimson to purplish red, $20$–$60\mathrm{mm}$ long. Main axes distinctly flattened, often narrower at base, ultimate branches short, often opposite, spine-like or spathulate [32].

3.3.58.2 Habitat

In sheltered locations below the tidal mark.

3.3.58.3 Distribution

NE Atlantic (Ireland and Britain to Canary Islands); Mediterranean; Indo-Pacific (Indonesia).

3.3.58.4 Uses and Compounds

Source of Agar [506]. Extracts have antiviral, cytotoxic, and antibacterial activity [205, 507].

3.3.59 Pterocladiella capillacea (S.G. Gmelin) Santelices and Hommersand

3.3.59.1 Synonym

Pterocladia capillacea (S.G. Gmelin) Bornet.

3.3.59.2 Common Name

Small agar weed.

3.3.59.3 Description

Thallus dark brownish red, commonly grows in dense tufts about $4\mathrm{cm}$ high, and composed of prostrate axes that give rise to the flattened erect axes: branching pinnate to irregularly opposite with uniaxial growth from single apical cells; inner structure pseudoparenchymatous, with long, slender, thick-walled rhizine cells filling the spaces between elongated medullary cells that are surrounded by a three-layered cortex of smaller pigmented cells [508].

3.3.59.4 Habitat

In large pools and lagoons in the lower littoral and shallow sublittoral, widely distributed, never common.

3.3.59.5 Distribution

Europe, Atlantic Islands, N America, Caribbean Islands, S America, Africa, SW and SE Asia, Australia and New Zealand, Pacific Islands.

3.3.59.6 Uses and Compounds

Source of agar [509, 510]. Extracts have antioxidant [234], antibacterial [470], antinociceptive and anti-inflammatory [511], anticoagulant [512], and antitumor [126] activity.

• Order: Gigartinales

3.3.60 Ahnfeltiopsis devoniensis (Greville) P.C. Silva & DeCew

3.3.60.1 Synonym

Gymnogongrus devoniensis (Greville) Schotter

3.3.60.2 Description

A. devoniensis is a small red marine alga that grows to only several centimeters in length from a disk-like holdfast (Fig. 6.26). It forms a medium-sized flattened frond with regular dichotomous branching. The branches have parallel sides. The reproductive structures (cystocarps) are internal [513].

Fig. 6.26

Ahnfeltiopsis devoniensis specimen

3.3.60.3 Habitat

Generally found in the very lower intertidal or shallow sublittoral, in salty areas protected from strong wave action. As far as it is known, it can be found anytime.

3.3.60.4 Distribution

NE Atlantic (Britain to Portugal).

3.3.60.5 Uses and Compounds

Source of carrageenan [514, 515, 516]. Extracts have antihypertensive and antioxidant activity [501, 517].

3.3.61 Calliblepharis ciliata (Hudson) Kützing

3.3.61.1 Common Name

Eyelash weed.

3.3.61.2 Description

C. ciliata is bright to dark red in color. The main blade is erect and forms into a wedge shape or ovate lobe that expands into a dichotomous or irregularly divided blade up to $7\mathrm{cm}$ broad and $30\mathrm{cm}$ long and $350$–$650\mathrm{\mu }\mathrm{m}$ thick. Small branches arise from the main blade. It can vary considerably in blade width and degree of subdivision. In southeastern England its blades are often only $10$–$15\mathrm{\mu }\mathrm{m}$ thick. The branchlets (proliferations) that arise from the margins of the blade are either pointed or rounded. Patches of encrusting bryozoans are very common on old specimens [518, 519].

3.3.61.3 Habitat

In larger lower intertidal pools and sublittoral ($0$–$25\mathrm{m}$) on stones, maerl, and shells, widely distributed, common in south and west, sometimes frequent in drift.

3.3.61.4 Distribution

NE Atlantic (Ireland and Britain to Mauritania); W Mediterranean.

3.3.61.5 Uses and Compounds

Source of carrageenan [520, 521], and hemagglutinins [375].

3.3.62 Calliblepharis jubata (Goodenough & Woodward) Kützing

3.3.62.1 Description

C. jubata is brownish red in color. It has a thallus consisting of a branched holdfast that gives rise to an erect frond that expands into a dichotomous or irregularly divided blade (Fig. 6.27). The outline of the frond is variable but it commonly has a cylindrical or very slightly compressed stipe. Its blades are about $6\mathrm{mm}$ broad and $30\mathrm{cm}$ long with narrow branches. The branches appear long and tendril like. Long branchlets (proliferations) arise from the blade surface and margins of the branches [1].

Fig. 6.27

Calliblepharis jubata specimen

3.3.62.2 Habitat

On rocks and epiphytic, especially on C. officinalis in large open pools, mid-littoral to shallow sublittoral ($5\mathrm{m}$).

3.3.62.3 Distribution

NE Atlantic (Ireland to Mauritania); W Mediterranean.

3.3.62.4 Uses and Compounds

Source of carrageenan [514, 515, 516, 521, 522, 523], and hemagglutinins [375]. Extracts have antimycobacterial [317], anticoagulant [524], antiprotozoal, and cytotoxic [525] activity.

3.3.63 Caulacanthus ustulatus (Mertens ex Turner) Kützing

3.3.63.1 Description

Thalli forming small dense entangled tufts of up to $5\mathrm{cm}$, reddish-brown color, which blackens by desiccation, with rough touch; fixed to the substrate by cylindrical, crawling axes from which derive others, also with circular section, irregularly branched; ramifications with acute apices and behaving small triangular-shaped spines [526].

3.3.63.2 Habitat

It lives on rocks and clams in well-lighted areas with little inclination at mid-littoral zones in semiexposed shores.

3.3.63.3 Distribution

NE and E Atlantic (Ireland and Britain to Guinea); Mediterranean; NW Atlantic (Canada to Mexico); SW Atlantic (Brazil); SE Atlantic (Angola to South Africa); Indian and Pacific Oceans; Australia.

3.3.63.4 Uses and Compounds

Produces a kappa/iota-hybrid carrageenan [527]. Extracts have antibacterial activity [358].

3.3.64 Chondracanthus acicularis (Roth) Fredericq

3.3.64.1 Description

Cartilaginous, cylindrical, or compressed, purple-red or blackish fronds, sometimes with greenish or whitish spots, to $100\mathrm{mm}$ long, irregularly bipinnately branched, branches curved, sharply pointed [1].

3.3.64.2 Habitat

On rocks, lower intertidal, generally uncommon but may be locally common on sheltered, silty shores in the lower intertidal.

3.3.64.3 Distribution

NE and E Atlantic (Ireland and Britain to Cameroon); Mediterranean; NW and SW Atlantic; Caribbean; Indian Ocean; Pacific (Hawaii); E Australia.

3.3.64.4 Uses and Compounds

Source of carrageenan [514, 515, 516]. Extracts have antiviral [103], antibacterial [269, 357], antioxidant [429], antifungic [204], and anticoagulant [512] activity.

3.3.65 Chondracanthus teedei var. lusitanicus (Rodrigues) Bárbara & Cremades

3.3.65.1 Description

The fronds of this alga are cartilaginous-membranous, with purple-violet color that darkens by desiccation, becoming greenish yellow with decay (Fig. 6.28). The main axes of the fronds, as their ramifications are wide, reaching $1\mathrm{cm}$ in the older portions. This species is confused sometimes with Calliblepharis jubata [1].

Fig. 6.28

Underwater photo of Chondracanthus teedei var. lusitanicus

3.3.65.2 Habitat

On rocks in mid-littoral zone.

3.3.65.3 Distribution

NE Atlantic (Spain and Portugal).

3.3.65.4 Uses and Compounds

Produces carrageenan [514, 515, 516, 528]. Extracts have cytotoxic activity [529].

3.3.66 Chondrus crispus Stackhouse

3.3.66.1 Description

Cartilaginous, dark purplish red, red, yellowish or greenish fronds of $150\mathrm{mm}$ high, gametophyte plants are often iridescent under water when in good condition; stipe compressed, narrow, expanding gradually to a flat, repeatedly dichotomously branched frond, in tufts from a discoid holdfast. Axils rounded, apices blunt or subacute, frond thicker in center than margins; breadth of segments varies frequently; branching, color, and thickness also vary frequently.

Highly variable (polymorphous) thalli may reach $15\mathrm{cm}$ long, cartilaginous consistency and reddish-pink or -brown color and iridescent in water. These algae are fixed by a disk whose first unbranched stipe gradually expands into a fan-like blade, repeatedly dichotomously divided, with ends rounded or truncated. Small dilations (2–3 mm in diameter), which are the reproductive structures may appear on the surface of the blades [1].

3.3.66.2 Common Names

Irish moss, Carrageen moss, Jelly moss.

3.3.66.3 Habitat

On rocks, lower intertidal and shallow sublittoral, in pools in the mid-littoral in some locations; widely distributed in the northwestern and northeastern Atlantic, often abundant.

3.3.66.4 Distribution

C. crispus has a wide distribution. It includes the northwest Atlantic from Labrador and the Maritime Provinces in Canada southward to New Jersey and Delaware in the United States. It can be found to a  limited extent in the western Baltic Sea, from northern Russia and Norway to southern Spain, spanning the northeast Atlantic, the North Sea, and the English Channel. It can be found in the Mediterranean, Portugal, the Azores, the Faroes, and West Africa, as well as in the Bering Sea from Russia to Alaska.

3.3.66.5 Uses and Compounds

C. crispus is harvested as a common source of the polysaccharide carrageenan, which is extracted from cell walls and forms a gel that is used commercially as a  thickener [4, 514, 515, 516].

The gelling and thickening properties of carrageenan are used widely in the cosmetics, food, and pharmaceutical industries. Examples of applications include making ice cream and air fresheners, beer clarification, and treatment for coughs and diarrhea [109, 530, 531].

Extracts have antifouling and antibacterial [532, 61], antioxidant, and antimicrobial [205, 373, 533].

3.3.67 Cystoclonium purpureum (Hudson) Batters

3.3.67.1 Description

Rather soft, cylindrical, dull-purplish pink fronds, $3\mathrm{mm}$ wide, to $600\mathrm{mm}$ long. Branches numerous, alternate, branchlets tapered at both ends; branches sometimes drawn out into long twisting tendrils; multiaxial, medulla a cordlike strand of loosely interwoven, narrow filaments, surrounded by large, rounded cells, with outer layer of small, angular, assimilatory cells; said to have an onion-like smell shortly after collection [534].

3.3.67.2 Habitat

On rocks and stones in mid-littoral and in shallow sublittoral, generally distributed, abundant.

3.3.67.3 Distribution

North Atlantic (Arctic Canada to Spain); North Sea (Helgoland); Baltic, Mediterranean (Greece), Indian Ocean (Pakistan), Australia (Queensland).

3.3.67.4 Uses and Compounds

Source of carrageenan [32, 521, 535]. Extracts have nematicide [536], antibacterial [358, 537, 86], and anticoagulant [375] activity.

3.3.68 Dilsea carnosa (Schmidel) Kuntze

3.3.68.1 Common Name

Red rags.

3.3.68.2 Description

One of the larger red seaweeds, D. carnosa is tough and leathery (Fig. 6.29). Several dark reddish brown, flat, blades gradually expand from a single disk-shaped holdfast, and have short cylindrical stipes. The blades do not have a midrib or veins and are simple wedge or spoon shaped. The blades can be $15$–$30\mathrm{cm}$ long and $5$–$20\mathrm{cm}$ wide. Older blades may be split from the margin toward the base but the rounded oblong (obovate) shape of the blade is never quite lost [1, 538].

Fig. 6.29

Dilsea carnosa specimens

3.3.68.3 Habitat

On rocks in shady pools, lower intertidal on rock, and shallow sublittoral to $25\mathrm{m}$, usually on rock in kelp forests; widely distributed, common.

3.3.68.4 Distribution

NE Atlantic (Iceland and Spitsbergen to Portugal).

3.3.68.5 Uses and Compounds

Produces carrageenan [539, 540], and extracts antisettlement [257], antiprotozoal [525], antifungal [541], and antifouling [542] activity.

3.3.69 Dumontia contorta (S.G.Gmelin) Ruprecht

3.3.69.1 Description

Erect thallus, cylindrical when young, compressed when older, tubular-hollow, brownish red to crimson-purple, often yellow-brown at the tips. Thallus with irregular simple lateral branches, tapering at both ends, sometimes slightly swollen, often twisted around the longitudinal axis; soft, gelatinous. Holdfast a small, persistent disk, expanding with age [32].

3.3.69.2 Habitat

On rocks and pebbles, shallow open pools, upper intertidal to shallow sublittoral, common, widely distributed.

3.3.69.3 Distribution

NE Atlantic (Spitsbergen to Portugal, North Sea); NW Atlantic; NW Pacific (Russia, Japan); NE Pacific (Alaska).

3.3.69.4 Uses and Compounds

Extracts have antiviral [543], and antioxidant [429] activity.

3.3.70 Furcellaria lumbricalis (Hudson) J.V. Lamouroux

3.3.70.1 Common Names

Clawed fork weed, black carrageen.

3.3.70.2 Description

Cartilaginous, cylindrical, brownish-black fronds, repeatedly dichotomously branched, fastigiate, to $2\mathrm{mm}$ diameter and $300\mathrm{mm}$ long, with acute apices; attached by much-branched rhizoids. Multiaxial, medulla of cylindrical cells interspersed with rhizoids, cortex of irregular filaments, inner cells elliptical, outer cells narrow, elongated, in radial rows [544].

3.3.70.3 Habitat

On rocks, lower intertidal and shallow sublittoral, in pools and runnels, in open situations, often on sandy and muddy shores, tolerating lowered salinities.

3.3.70.4 Distribution

North Atlantic (Nova Scotia, Greenaland); NE Atlantic (Faroe Islands, Ireland and Britain to Spain), North Sea (Scandinavia, Hegoland), Baltic; W Mediterranean (Spain, Sardinia, Sicily); Indian Ocean (India, Pakistan).

3.3.70.5 Uses and Compounds

Source of hybrid carrageenan (Furcellaran) [32, 545]. The sulfated polysaccharides of this species have immunostimulation activity [546].

3.3.71 Gigartina pistillata (S.G. Gmelin) Stackhouse

3.3.71.1 Description

G. pistillata (Fig. 6.30) is the type species of the genus Gigartina and their thalli are erect, up to $20\mathrm{cm}$ tall, dark red or red-brown, cartilaginous, elastic, dichotomously branched, attached to the substrate through a small disk [1].

Fig. 6.30

Underwater photo of Gigartina pistillata

3.3.71.2 Habitat

On firm substrata in the intertidal zone, to $12\mathrm{m}$ depth.

3.3.71.3 Distribution

NE Atlantic (Ireland and Britain to Senegal); SE Atlantic (South Africa).

3.3.71.4 Uses and Compounds

Source of carrageenan – (female gametophytes) produces a hybrid carrageenan, $48.7\mathrm{kappa}$, $44.5\mathrm{iota}$ (% mol). G. pistillata (tetrasporophytes) produces a hybrid carrageenan xi-lambda [547]. The sulfated polysaccharides of this species have antitumor [548], antiviral [549], anti-inflammatory [550], and antioxidant [429, 551] activity.

3.3.72 Gymnogongrus crenulatus (Turner) J. Agardh

3.3.72.1 Description

Cartilaginous, fleshy, flattened, dark red fronds, to $100\mathrm{mm}$ high, with short cylindrical stipe from basal disk; repeatedly dichotomous, branches strap-shaped, apices rounded, often paler than rest of frond. Reproductive structures appear as external, wart-like excrescences [552].

3.3.72.2 Habitat

Epilithic, lower littoral in pools and emergent, and sublittoral to $13\mathrm{m}$, tolerant of sand cover; plants typically encrusted with species of Bryozoa, Foraminifera, and calcareous algae.

3.3.72.3 Distribution

NE Atlantic (Ireland and Britain to Mauritania, Canary Islands, Cap Verde Islands); NW Atlantic (New Brunswick to Massachusetts); Australia.

3.3.72.4 Uses and Compounds

G. crenulatus produce a hybrid carrageenan ($64.1\mathrm{kappa}$, $30.8\mathrm{iota}\mathrm{\%}\mathrm{mol}$) [547]. The sulfated polysaccharides of this species have antibacterial activity [130].

3.3.73 Gymnogongrus griffithsiae (Turner) Martius

3.3.73.1 Description

Cartilaginous, cylindrical to compressed, brownish red to blackish-purple fronds, to $75\mathrm{mm}$ high, from an expanded discoid base; repeatedly dichotomous, fastigiate, with rounded, somewhat flattened apices [553].

3.3.73.2 Habitat

Epilithic, littoral in pools and emergent, upper sublittoral; tolerant of sand cover. On sand-covered rocks, lower intertidal, rare [518].

3.3.73.3 Distribution

NE and E Atlantic (Ireland to W Africa); Mediterranean; NW to SW Atlantic (North and South Carolina, Brazil, Uruguay); Caribbean; Australia.

3.3.73.4 Uses and Compounds

Produces sulfated galactans – carrageenans [554] with antioxidant [205], and antiviral [555, 556, 557] activity.

3.3.74 Hypnea cornuta (Kützing) J. Agardh

3.3.74.1 Description

Plants caespitose or loosely intricate-caespitose, up to $30\mathrm{cm}$ in length, soft in texture and reddish brown in color; axes subterete, up to $1\mathrm{mm}$ in diameter at the base, pointed at the apex, spirally branched up to the fourth order; branching angle less than $908$; axes and branches loosely clothed with stellate processes; branches up to $550\mathrm{\mu }\mathrm{m}$ in diameter, and spinous ultimate branchlets, $60$–$70\mathrm{\mu }\mathrm{m}$ in diameter, slightly constricted at their base; extensive basal system of prostrate axes attached by secondary discoid holdfasts produced by the cortical cells at any axis level [558].

3.3.74.2 Habitat

In mid-littoral rock pools exhibit the habit of free-floating plants, while in the open sea it throve attached on rocks within $-$ $50\mathrm{cm}$.

3.3.74.3 Distribution

W Atlantic (USA to Brazil); Mediterranean; Caribbean (Cuba); Indian Ocean; NW Pacific (Japan); Indonesia; Australia.

3.3.74.4 Uses and Compounds

Produces carrageenan [559].

3.3.75 Hypnea musciformis (Wulfen) J.V. Lamouroux

3.3.75.1 Common Names

Hook weed, Hooked seaweed, Hypnea.

3.3.75.2 Description

H. musciformis is a red alga with loosely intertwined cylindrical branches that form clumps or masses up to $20\mathrm{cm}$ tall, though plants are often broken by wave action before they reach full size (Fig. 6.31). Branches are firm and highly irregularly branched, narrowing to broad, flattened, tendril-like hooks. These hooks make H. musciformis easily distinguished from all other Hypnea species found in similar Habitats. Holdfasts are small or lacking because the plants usually anchor themselves by attaching to other species such as Sargassum (for example, Sargassum muticum). The tissue is usually a dark reddish brown, though when growing in nutrient poor water color can pale to yellowish brown. It is found abundantly in shallow coastal waters where it prefers calm, shaded sublittoral reef flats, though it also grows in tide pools and rocky intertidal areas. In bloom stage, it may be found free floating. H. musciformis is also a highly opportunistic invader [560].

Fig. 6.31

Herbarium specimen of Hypnea musciformis (MACOI no. 3733)

3.3.75.3 Habitat

Common on calm intertidal and shallow sublittoral reef flats, tide pools and on rocky intertidal benches. Most often found low intertidal to shallow sublittoral reef flats, attached to sandy flat rocks.

3.3.75.4 Distribution

NE Atlantic (Spain and Portugal to Canary Islands), E and SE Atlantic (W Africa); NW Atlantic (Georgia, N. Carolina); SW Atlantic (Brazil, Uruguay); Caribbean; Mediterranean; Red Sea, Indian Ocean and Indo-Pacific; Pacific Islands (Hawaii; Fiji); Australia.

3.3.75.5 Uses and Compounds

In some areas, H. musciformis is grown for harvest of kappa carrageenan [561, 562]. It also contains a high amount of natural occurring antioxidants, and is nourishing to the skin. H. musciformis is used in over $100$ hair color and hair care products such as shampoos, conditioners, and styling gels, it is used in more than $20$ sunless tanning products, and in many antiaging creams and applications. H. musciformis is used in facial treatments, toners, and moisturizers, makeup and cosmetics, and eye treatments. H. musciformis is also commonly joined by Gelidiella acerosa and Sargassum filipendula as an effective seaweed ingredient set for personal care products [109, 560].

Extracts have antiviral [238], antifungal [563, 564], antitumoral [421, 565], antihelminthic [566], psychotropic and anxiolytic [567], antibacterial [242, 38, 421, 568, 569, 70], cytotoxic, antioxidant, larvicidal, and antifeed [242, 570, 571] activity.

3.3.76 Hypnea spinella (C. Agardh) Kützing

3.3.76.1 Description

Fragile, upright, or in tangled mats, to $15\mathrm{cm}$ high, light brown-red, rose-red or bleached; branching in all directions; branches $0.4$–$1.0\mathrm{mm}$ diameter, cylindrical. Branchlets spine-, spur-, or tendril-like, numerous, spirally arranged, to $2.5\mathrm{mm}$ long, occasionally longer; apices tapering, pointed, slightly up-curved. Cortex $1$–$2$ cells thick; cells rounded to irregular, $7.5$–$25.0\mathrm{\mu }\mathrm{m}$ diameter, densely pigmented; medullary cells thick-walled, irregular to ovoid, $100$–$320\mathrm{\mu }\mathrm{m}$ diameter, surrounding obvious thick-walled central filament ($70$–$80\mathrm{\mu }\mathrm{m}$ diameter); holdfast initially disk-like. Tetrasporangia ovoid, $10$–$23\mathrm{\mu }\mathrm{m}$ diameter, $25$–$49\mathrm{\mu }\mathrm{m}$ long, zonately divided, in swollen sori (nemathecia) girdling middle part of lateral branchlet; cystocarps spherical, $100$–$900\mathrm{\mu }\mathrm{m}$ diameter, solitary or clustered at base to middle of branchlet [572].

3.3.76.2 Habitat

Attached to small shells or rubble, often entangled in seagrass beds; lower intertidal to $7\mathrm{m}$ (reported to $27\mathrm{m}$) deep.

3.3.76.3 Distribution

Warm E Atlantic (Atlantic Islands, W coast of Africa); Mediterranean; Caribbean; NW Pacific (Japan, China); Pacific Islands (Hawaii); Indo-Pacific (Philippines, Vietnam); E Pacific (Mexico, Ecuador); Australia.

3.3.76.4 Uses and Compounds

This is an edible species, being commonly eaten (boiled in coconut milk) in other parts of the Pacific and Asia [573]. Extracts have antifungal [204], and immunomodulatory [394] activity.

3.3.77 Mastocarpus stellatus (Stackhouse) Guiry

3.3.77.1 Common Name

False Irish moss.

3.3.77.2 Description

A small red alga (up to $17\mathrm{cm}$ in length), the fronds are channeled with a thickened edge and widen from a narrow stipe with disk-like holdfast (Fig. 6.32). The channeling is often slight and is most noticeable at the base of the frond. Mature plants have conspicuous growths of short, shout papillae (reproductive bodies) on the fronds. The plant is dark reddish brown to purple in color and may be bleached. The common name false Irish moss is used as it may be confused with C. crispus (Irish moss); the main features separating the two species being the channeled frond and appearance of reproductive bodies on mature plants [1].

Fig. 6.32

Mastocarpus stellatus specimen

3.3.77.3 Habitat

This alga is found on rocky shores, particularly in very exposed areas where it grows among barnacles and mussels, on less exposed shores it is often abundant under fucoids.

3.3.77.4 Distribution

NE Atlantic (Scandinavia to Mauritania, North Sea); NW Atlantic (Newfoundland and Nova Scotia to Rhode Island).

3.3.77.5 Uses and Compounds

Source of carrageenan [514, 515, 516]. Extracts have antioxidant activity [205, 373, 429, 574].

3.3.78 Phyllophora crispa (Hudson) P.S. Dixon

3.3.78.1 Description

Bright red or pink seaweed. Each plant has a small disk-shaped base and erect fronds. The fronds consist of short cylindrical stipes (stalks) rarely longer than $1\mathrm{cm}$ long and blades which may be up to $15\mathrm{cm}$ long and $10\mathrm{mm}$ wide. The fronds are dichotomously branched, with undulating margins and an indistinct midrib. The tip of each frond is distinctly rounded. The fronds are perennial and in some case five or six new periods of growth can be identified. Regeneration occurs following erosion or animal grazing. Continual regeneration leads to great variation in the appearance of individual plants as each new growth could come from the end, margin or surface of the blade. Fronds are frequently encrusted with the spiral tube worm Spirorbis spirorbis or bryozoans [575].

3.3.78.2 Habitat

Frequent in shady pools in lower intertidal and on rock subtidally to $30\mathrm{m}$.

3.3.78.3 Distribution

NE Atlantic (Scandinavia to Canary Islands, North Sea); W Mediterranean; Black Sea; Free-floating forms in the Baltic Sea.

3.3.78.4 Uses and Compounds

Raw material for the agar production on the Black Sea [32]. Extracts have antifungal activity [62].

3.3.79 Polyides rotundus (Hudson) Gaillon

3.3.79.1 Common Names

Discoid forked weed, Goat tang.

3.3.79.2 Description

Dark red or blackish seaweed with smooth, cartilaginous, cylindrical fronds, branching dichotomously in roughly the same plane. The fronds rise from a fleshy, discoid holdfast up to $2\mathrm{cm}$ in diameter. The reproductive bodies occur as oval-shaped swellings along the sides of the branches or occasionally encircling them. The seaweed grows up to $20\mathrm{cm}$ in length [576].

3.3.79.3 Habitat

On rocks and stones in open sandy pools and runnels, lower intertidal and shallow sublittoral.

3.3.79.4 Distribution

N and NE Atlantic (Arctic Ocean to Iberian Peninsula, Baltic); NW Atlantic (Arctic Canada to New York).

3.3.79.5 Uses and Compounds

Extracts have antifouling activity [532].

3.3.80 Solieria chordalis (C. Agardh) J. Agardh

3.3.80.1 Description

Thallus tufted, vividly red, axes cylindrical, thin, only sparsely branching at first, later characteristically with relatively long, unilaterally inserted appendices, height to $20\mathrm{cm}$ [577].

3.3.80.2 Habitat

In sheltered localities below the mid-littoral zone on rocks.

3.3.80.3 Distribution

NE Atlantic (from N France to S Morocco), Mediterranean.

3.3.80.4 Uses and Compounds

Source of carrageenan [521, 578, 579, 580, 581]. Extracts have hemagglutinating [375], and Immunostimulation [581] activity.

3.3.81 Sphaerococcus coronopifolius Stackhouse

3.3.81.1 Common Name

Berry wart.

3.3.81.2 Description

Narrow, compressed, two-edged, cartilaginous, scarlet fronds, main axes dark brownish red, to $300\mathrm{mm}$ long; branching abundant, distichous, subdichotomous or alternate, terminal branchlets acute, fringed with short marginal proliferations. Tetrasporophyte is Haematocelis fissurata, a thick crust with oily fissures, with which it is sometimes found [582].

3.3.81.3 Habitat

Rarely on rocks in lower littoral, often common in the shallow sublittoral to $15\mathrm{m}$.

3.3.81.4 Distribution

E Atlantic (Ireland and Britain to Canary Islands); Mediterranean, the Black Sea.

3.3.81.5 Uses and Compounds

Extracts have antifouling [583], cytotoxic and antimitotic [332, 584, 585, 62], antiviral [586], antibacterial and antifungal [275, 62], activity.

3.3.82 Stenogramma interruptum (C. Agardh) Montagne

3.3.82.1 Description

Cartilaginous, flattened, bright-red fronds, to $70\mathrm{mm}$ high, shortly stipitate from the discoid base. Lamina fan-shaped, $\pm$dichotomously divided, segments about $10\mathrm{mm}$ wide, with rounded apices, margin usually smooth, rarely proliferous; reproductive structures often occurring in a clearly visible, often discontinuous, midrib over the surface of the fronds [587].

3.3.82.2 Habitat

Epilithic, sublittoral to $13\mathrm{m}$, in sheltered areas on small stones among gravel and mud [518]. On rocks, stones, etc., sublittoral, southern and western coasts, occasional.

3.3.82.3 Distribution

NE Atlantic (Ireland and Britain to Morocco); West of Atlantic (Canada to Brazil); E and W Pacific (Japan, Mexico, Ecuador, Chile, Peru); Australia and New Zealand.

3.3.82.4 Uses and Compounds

Produces carrageenan – polysaccharides from tetrasporic plants (lambda-carrageenan) of S. interruptum showed higher anticoagulant activity than those isolated from cystocarpic (kappa/iota-carrageenan) plants [512, 588]. Extracts have also antiviral activity [35, 549].

• Order: Gracilariales

3.3.83 Gracilaria bursa-pastoris (S.G. Gmelin) P.C. Silva

3.3.83.1 Description

Growing in tufts to $30\mathrm{cm}$ long, much branched usually simply forked or alternate rarely opposite; somewhat compressed, but not flat. Thallus greenish red, yellow greenish to dark brownish red, with cylindrical axes, forking and with lateral branching, tufted, erect, branches gradually tapering off, not narrowing at their origins, the cystocarp-bearing plants are densely covered with hemispherical reproductive structures (cystocarps); texture cartilaginous-meaty, stiff, bristly; discoid holdfast [32].

3.3.83.2 Habitat

Epilithic, on calmer water of the upper sublittoral.

3.3.83.3 Distribution

NE Atlantic (Ireland to Cape Verde Islands, Kenya); Mediterranean, Indo-Pacific Oceans (India, Sri Lanka, Philippines, Singapore, Japan, China, Hawaiian Islands, Florida, Mexico); Caribbean (Cuba) and SW Atlantic (Brazil).

3.3.83.4 Uses and Compounds

Source of agar [589] and used directly as food and for animal feed [290, 32]. Extracts have antibacterial [171], anticoagulant [375] activity.

3.3.84 Gracilaria gracilis (Stackhouse) Steentoft, L.M. Irvine & Farnham

3.3.84.1 Common Name

False Ceylon moss.

3.3.84.2 Description

Cartilaginous, cylindrical, dull-purple fronds, to $500\mathrm{mm}$ long, one or several are arising from small, fleshy, perennial discoid holdfast (Fig. 6.33). Branching very irregular, sparse or profuse, branches to $2\mathrm{mm}$ diameter, apices pointed; intertidal tissue of large thin-walled cells with narrow outer cortical zone of small colorless cells [2, 590].

Fig. 6.33

Underwater photo of Gracilaria gracilis

3.3.84.3 Habitat

On rocks and stones, intertidal and sublittoral, especially on sandy shores, generally distributed, common.

3.3.84.4 Distribution

Temperate-warm to warm NE and E Atlantic (Ireland to Canary Islands, W Africa); SE Atlantic (South Africa); Mediterranean; Caribbean; W Atlantic (Brazil); NW Pacific (Russia, Japan); NE Pacific (Alaska to California, Mexico); Pacific Islands; Indo-Pacific Ocean; Australia; Antarctica.

3.3.84.5 Uses and Compounds

Source of agar [32, 523, 591, 592, 593] and used directly for animal feed [594]. Extracts have antimicrobial [276, 569], and antioxidant [350, 595] activity.

3.3.85 Gracilaria multipartita (Clemente) Harvey

3.3.85.1 Description

G. multipartita is a translucent, dull purple or reddish-brown alga which has fronds that measure up to $25\mathrm{cm}$ long. It is cartilaginous, very brittle, and has a compressed stipe [1].

3.3.85.2 Habitat

Grows on rocks or other hard substrata, tolerating a wide degree of wave exposure. Recorded from the upper sublittoral to a depth of $15\mathrm{m}$. G. multipartita is also tolerant of sand.

3.3.85.3 Distribution

NE Atlantic (Britain to Senegal); Atlantic Islands; Mediterranean (Italy, Spain).

3.3.85.4 Uses and Compounds

Source of agar [596]. Extracts have antibacterial [269, 358, 597, 598], and antifungal [284, 286] activity.

3.3.86 Gracilaria vermiculophylla (Ohmi) Papenfuss

3.3.86.1 Common Name

Komulkosiraegi.

3.3.86.2 Description

G. vermiculophylla is a red macroalga that is cartilaginous, cylindrical, and up to $50\mathrm{cm}$ long. It is coarsely branched, often profusely so. It can be found as loose-lying thalli or attached to small stones or shells. Red algae are often found in the vegetative state, and the characterization of reproductive structures is often necessary for correct identification of Gracilaria species [599, 600, 601].

3.3.86.3 Habitat

Estuarine habitats, marine habitats, mainly in salinity lagoons. It is well adapted to low energy, shallow-bottom bays, lagoons, estuaries, harbors, and inslets [602].

3.3.86.4 Distribution

Native range – NW Pacific ocean including Japan and E Asia [601]; Introduced range – N American E and W coasts, Europe, NE Atlantic coast extending from Morocco to SW Sweden, E Pacific [603, 604].

3.3.86.5 Uses and Compounds

G. vermiculophylla is widely collected for the production of Agar, which is used extensively in the pharmaceutical and food industries [592, 605, 606, 607]. Extracts have antibacterial [449], and antioxidant [335, 608] activity.

3.3.87 Gracilariopsis longissima (S.G. Gmelin) M. Steentoft, L.M. Irvine & W.F. Farnham

3.3.87.1 Description

Thalli are from almost simple to profuse and irregularly branched, with the slender cylindrical axis throughout the plant. Cystocarps are scattered throughout the thallus, protruding from the thallus surface. Spermatia are formed in near the surface of the thallus. Tetrasporangia are cruciate and are scattered in the cortex [609].

3.3.87.2 Habitat

Usually lives in the sublittoral environment, on loamy or sandy funds shells or gravel.

3.3.87.3 Distribution

NE Atlantic (Britain to Portugal); SE Atlantic (Namibia, South Africa).

3.3.87.4 Uses and Compounds

Source of agar [592, 605]. Extracts have antibacterial [569, 610, 611] activity.

• Order: Halimeniales

3.3.88 Grateloupia filicina (J.V. Lamouroux) C. Agardh

3.3.88.1 Description

Compressed, tufted, dark purplish brown fronds, to $120\mathrm{mm}$ high, main axis $1$–$4\mathrm{mm}$ broad. Once or twice pinnate, axes and branchlets tapered at base and apex. This is a soft limp and slippery smooth seaweed with somewhat flattened branches that can be red green brown or almost black. Size and shape vary greatly from $0.5$–$5\mathrm{mm}$ wide to $2$–$30\mathrm{cm}$ long, with either few or many branches [612].

3.3.88.2 Habitat

On rocks in pools; mid-littoral to shallow sublittoral, sporadic, often locally common.

3.3.88.3 Distribution

Worldwide in warm and temperate-warm seas.

3.3.88.4 Uses and Compounds

Used as food and source of Carrageenan [613, 614, 615]. Extracts have antioxidant [350, 595, 615, 616, 617], antimicrobial [34], antiviral [615, 618, 619], anticoagulation [615, 620, 621] activity.

3.3.89 Grateloupia turuturu Yamada

3.3.89.1 Description

Thallus flat, membranous, with short stipe, the single fronds linear to broad-lanceolate, undivided or irregularly dividing from the base, narrowing toward the base as well as the tip (Fig. 6.34); sometimes proliferating on the margins and the surface; consistency gelatinous-slippery but firm; discoid holdfast; violet- to crimson-red, often greenish at the top thallus [32].

Fig. 6.34

Underwater photo of Grateloupia turuturu

3.3.89.2 Habitat

Epilithic in shallow tide pools and on sand-covered rocks near coast.

3.3.89.3 Distribution

SE Pacific (Chile), SW Atlantic (Peru), G. turuturu is considered native to Japan, China, and Korea, but has spread to the NE Atlantic, the Mediterranean, South America, Australia, and New Zealand.

3.3.89.4 Uses and Compounds

In Japan, this seaweed is commonly used as a sea vegetable [622]. G. turuturu is characterized by its richness in dietary fiber (nearly 60% DW) and therefore appears to be a good source of food fiber for human consumption. This is very interesting because the beneficial effect of fiber on health is already well known [623, 624]. This seaweed is also rich in proteins, like Palmaria palmata, another red alga now authorized in France as a sea vegetable. Its lipid content is low, like all red seaweeds used in human nutrition, and its eicosapentaenoic acid content is similar to those reported for edible red seaweeds such as Chondrus cripus or Gracilaria verrucosa [625].

Extracts have antifouling [586], antibacterial [626], anticoagulant [512], antioxidant [627], and antiviral [278] activity.

• Order: Nemaliales

3.3.90 Galaxaura rugosa (J. Ellis & Solander) J.V. Lamouroux

3.3.90.1 Synonym

Galaxaura elongata J. Agardh.

3.3.90.2 Description

Thallus bushy, stiff, compact, forming hemispherical mounds, $5$–$7$ $(-12)\mathrm{cm}$ high, dark red-brown; branching irregularly dichotomous; calcification moderate. Branches cylindrical, $0.5$–$1.5$ $(-3)\mathrm{mm}$ diameter, densely but evenly covered by stiff hair-like filaments; holdfast inconspicuous. Tetrasporangia at apex of surface filaments, occasionally lateral near tip, spherical to oval, to $32\mathrm{\mu }\mathrm{m}$ diameter, cruciately divided [628].

3.3.90.3 Habitat

On firm substrata in calmer shallow water; found in up to $18\mathrm{m}$ depth.

3.3.90.4 Distribution

E Atlantic (Madeira, Canary Islands, Cap Verde to Gabon); W Atlantic (Brazil); Caribbean; Indian Ocean; NW Pacific (Japan, Philippines, Indonesia); Pacific Islands; Australia, New Zealand.

3.3.90.5 Uses and Compounds

Extracts have anti-inflammatory [629], antimicrobial [391, 72], antifungal, cytotoxic, and antiviral [72] activity.

3.3.91 Ganonema farinosum (J.V. Lamouroux) K.C. Fan & Yung C. Wang

3.3.91.1 Synonym

Liagora farinosa J.V. Lamouroux

3.3.91.2 Description

This alga is soft, smooth and about $13\mathrm{cm}$ tall. It is pinkish, lightly calcified, farinose and attached by small discoid holdfasts. The branching pattern is basically dichotomous, with interdichotomal lengths decreasing toward terminal portions of the thallus. The branches are numerous, cylindrical, measuring about $1.5\mathrm{mm}$ in diameter, with forking apices into very short, acute and terminal branchlets [630].

3.3.91.3 Habitat

G. farinosum is found attached to rocky substrate among other algae in the sublittoral and intertidal areas exposed to air during low tides.

3.3.91.4 Distribution

G. farinosum is widely distributed in the tropical waters of the Atlantic, Pacific, and Indian Oceans; Mediterranean; In SE Asia, it has been recorded from Thailand, Vietnam, Malaysia, Indonesia (Irian Jaya) and the Philippines.

3.3.91.5 Uses and Compounds

Extracts have antibacterial [449], antifungal [204], cytotoxic, and antiviral [72] activity.

3.3.92 Liagora ceranoides J.V. Lamouroux

3.3.92.1 Description

Thallus to $11\mathrm{cm}$ high, pale pink to gray, lightly calcified, mucilaginous, irregularly or dichotomously branched every $2$–$20\mathrm{mm}$, with many proliferous lateral branches to $10\mathrm{mm}$ long; pressed specimens strongly adherent. Main axes to $2.5\mathrm{mm}$ in diameter basally, tapering to $0.2\mathrm{mm}$ near apices [631].

3.3.92.2 Habitat

From intertidal pools to $27\mathrm{m}$ depth, epilithic on Lobophora variegata; widespread in tropical seas.

3.3.92.3 Distribution

NE Atlantic (from France, Spain): Atlantic Islands; Mediterranean; NW Atlantic; Caribbean; SW and SE Atlantic; Indo-Pacific Oceans; Australia.

3.3.92.4 Uses and Compounds

Extracts have anticoagulant [206], and antioxidant [65] activity.

3.3.93 Liagora viscida (Forsskål) C. Agardh

3.3.93.1 Description

Thallus tufted, gray-purple to greenish white or pink, repeated dense branching at almost the same length, branches terete, tapering toward the top (Fig. 6.35); terminal branches usually spreading as wide-angled bifurcations, moderately calcified, texture flexible-firm [32].

3.3.93.2 Habitat

On firm substrata in shallow water to $5\mathrm{m}$ depth.

3.3.93.3 Distribution

NE and North Atlantic (France to Cap Verde Islands); Mediterranean; Indian Ocean (India, Sri Lanka); Pacific Islands (Fiji).

3.3.93.4 Uses and Compounds

Their endophytic fungi have antitumor and antimicrobial activity [632, 633].

3.3.94 Nemalion helminthoides (Velley) Batters

3.3.94.1 Description

Thallus cylindrical, reddish to purple brown, softly gelatinous, simple or sparingly dichotomously branched, to $2\mathrm{mm}$ wide, to $250\mathrm{mm}$ long, with discoid holdfast [634].

3.3.94.2 Habitat

On exposed rocky shores, generally growing on barnacles and limpets.

3.3.94.3 Distribution

NE Atlantic (Scandinavia to Canary Islands, W Africa); SW Atlantic (Brazil, Uruguay); Mediterranean; NW Pacific (Japan); NE Pacific (Alaska to Mexico); Australia, New Zealand.

3.3.94.4 Uses and Compounds

Used as food [634] and with dietary antioxidants [205, 429, 65]. N. helminthoides showed appreciable antiherpetic activity [635].

3.3.95 Scinaia furcellata (Turner) J. Agardh

3.3.95.1 Common Name

Southern scinà’s weed.

3.3.95.2 Description

Cylindrical, gelatinous but firm, clear pink to purplish-red fronds, $10\mathrm{mm}$ wide, $250\mathrm{mm}$ long, dichotomously branched from small discoid base (Fig. 6.36); constrictions at irregular intervals in mature plants [32].

Fig. 6.35

Liagora viscida specimen

Fig. 6.36

Scinaia furcellata specimen

3.3.95.3 Habitat

On stones, shells, and mal in the sublittoral ($30\mathrm{m}$), mainly in clear, unpolluted water; not common.

3.3.95.4 Distribution

NE and E Atlantic (S Norway to Morocco, Canary Islands to Congo); NW Atlantic; Mediterranean; Indian Ocean.

3.3.95.5 Uses and Compounds

Extracts have cytotoxic [636], antibacterial [130], and anticoagulant [637] activity.

• Order: Neamatomales

3.3.96 Schizymenia dubyi (Chauvin ex Duby) J. Agardh

3.3.96.1 Description

Erect leaf-like flat fronds, brow-red (liver-colored), translucent, gradually widening from the base, simple or irregularly split or lobed, then at a narrow angle, overlapping; often noticeably sickle-shaped, with smooth margin, not proliferating texture soft-slippery; cystocarps very small and sunken; very short stunted stipe, small discoid holdfast [32].

3.3.96.2 Habitat

Pools and on rock mid lower intertidal zone.

3.3.96.3 Distribution

NE Atlantic (Iceland to Morocco); Mediterranean; NW Pacific (Japan, China, Korea); Australia.

3.3.96.4 Uses and Compounds

Extracts have antioxidant [350], antitumor [638], antiviral, and anticoagulant [205, 546, 639, 640] activity.

• Order: Palmariales

3.3.97 Palmaria palmata (Linnaeus) Weber & Mohr

3.3.97.1 Common Name

Dulse, Grannogh, Dillisk, Handed focus.

3.3.97.2 Description

Reddish brown, membranous or leathery, flattened fronds, $50$–$300$ $(-1000)\mathrm{mm}$ long, arising from a discoid base, usually with a small stipe expanding gradually to form simple or dichotomously and palmately divided fronds, often with characteristic marginal leaflets (Fig. 6.37); blade very variable in shape, having broadly ovate to narrowly linear segments [641].

Fig. 6.37

Palmaria palmata specimen

3.3.97.3 Habitat

On rocks, mussels, and epiphytic on several algae, intertidal (at all levels but particularly near low water) and shallow sublittoral, especially on the upper part of L. hyperborea stip.

3.3.97.4 Distribution

P. palmata grows along the northern coasts of the Atlantic and Pacific oceans, as far north as Arctic Canada and Russia, and as far south as Portugal in Europe, and New Jersey and California in the United States. In the western Pacific, the southern range of P. palmata includes Japan and Korea.

3.3.97.5 Uses and Compounds

Dulse is good to eat, but only after being dried. In a fresh state it is leathery and unpalatable. After sun drying and proper storage, it is a very pleasant plant to chew. It has very little fat and only a small amount of proteins and cellulose, but is very rich in trace elements and vitamins, particularly vitamin A. Dulse contains large amount of several unusual carbohydrates including an unusual short-chained one, floridoside, and this can form up to $30\%$ of the dry weight. This may account for its palatability [642].

P. palmata is a good source of dietary requirements; it is rich in potassium, iron, iodine and trace elements, and relatively low in sodium. A small amount can provide more than $100\%$ of the daily amount of Vitamin B${}_6$, $66\%$ of Vitamin B${}_{12}$, iron, and fluoride. It has a slight nutty flavor, and has a long tradition in the cuisines of many Northern European cultures. P. palmata is also a traditional food in maritime North America, used in condiments, soups, and appetizers. Younger parts of the fronds are considered the most tender and edible. It can be eaten raw. P. palmata is also used as fodder for a variety of animals in many countries, as pet supplements, and sometimes as an agricultural fertilizer [4, 642, 643].

Extracts of this species have antioxidant [533, 644, 645, 646, 647], and antitumor [432, 644, 645] activity.

3.3.98 Rhodothamniella floridula (Dillwyn) Feldmann

3.3.98.1 Description

R. floridula is perennial brownish-red seaweed found on the lower shore. It usually covers large areas of rock in sandy habitats. At the base of the seaweed, filaments bind with sand to form a spongy, carpet like mass. The filaments are well-spaced and branch out up to $3\mathrm{cm}$ in length. Upright filaments of the seaweed uncovered by the ebbing tide appear as tufts of hair; when plants dry out they have a purplish tinge [648].

3.3.98.2 Habitat

Turf-forming on sand-covered rocks, mid- and lower intertidal, often under Fucus serratus; widely distributed, very common.

3.3.98.3 Distribution

NE Atlantic (Ireland and Britain to Portugal); SE Atlantic (Namibia, South Africa); SW Atlantic (Argentina).

3.3.98.4 Uses and Compounds

Used for the production of pharmaceuticals and functional foods [205]. Extracts have antioxidant activity [205].

• Order: Plocamiales

3.3.99 Plocamium cartilagineum (Linnaeus) P.S. Dixon

3.3.99.1 Common Names

Cock’s comb, Kammtang, Kamwier, Red comb weed.

3.3.99.2 Description

Bright scarlet seaweed up to $30\mathrm{cm}$ in length with branching fronds (Fig. 6.38). The branching occurs alternately along the fronds and becomes more frequent toward the tips. The general appearance of these seaweeds can greatly vary from very compact and closely branched to a much broader appearance with widely separated branching. The tips are incurving and ultimate branching occurs only to one side, giving a distinctive feathery or comb-like appearance [649].

Fig. 6.38

Underwater photo of Plocamium cartilagineum

3.3.99.3 Habitat

Temperate seas throughout the world; found on coasts of strong to moderate wave action and known from depths of $2$–$26\mathrm{m}$. Growing on L. hyperborea stipes and on other algae.

3.3.99.4 Distribution

NE Atlantic (Scandinavia to Senegal, North Sea), SE Atlantic (Namibia); Mediterranean; Indian Ocean (Pakistan, Mauritius); NW Pacific (Japan); Pacific Islands; NE Pacific (Alaska to California); SE-Pacific (Chile); Australia, New Zealand; Antarctica.

3.3.99.5 Uses and Compounds

Extracts with a red color are said to have been used for cosmetic purposes in ancient Rome [32].

P. cartilagineum is harvested commercially as the main raw material for the agar production on the Pacific coast of North America. Agar is widely used not only in laboratories as a growth medium for bacteria and other cultures, but in food and cosmetics as a gelling agent and stabilizer. It is a very pure, natural, firm gel. P. cartilagineum extracts are also high in lypolitic (lipid-digesting) sterols and as such is useful as an additive in slimming applications such as creams and massage products where it is able to provoke the release of fatty acids and eliminate surface fat, acting as a skin-firmer [650].

Extracts have antimicrobial [651], insecticidal [652], cytotoxic and antitumor [653], antioxidant [125], and antiviral [357, 549] activity.

• Order: Rhodymeniales

3.3.100 Botryocladia botryoides (Wulfen) Feldmann

3.3.100.1 Description

Plants rose-red to honey pink, erect, up to $11\mathrm{cm}$ in length, with irregular pseudodichotomous branching. Main axis and branches terete, $9$–$2.5\mathrm{mm}$ in diameter, of solid construction, composed of small pigmented, round to oval, cortical cells ($5\mathrm{\mu }\mathrm{m}$ diameter) that gradually increase in size thallus inward; medullary cells larger, hyaline, and ovoid, up to $50\mathrm{\mu }\mathrm{m}$. Axis and branches bearing pyriform vesicles [654, 655].

3.3.100.2 Habitat

Epilithic in depths up to $7\mathrm{m}$.

3.3.100.3 Distribution

NE Atlantic (Atlantic Islands), Western Atlantic [654].

3.3.100.4 Uses and Compounds

Extracts have antifungal activity [62].

3.3.101 Champia parvula (C. Agardh) Harvey

3.3.101.1 Description

Soft, gelatinous, pinkish red, much-branched fronds, densely matted, with blunt apices, to $100\mathrm{mm}$ high. Axes segmented, with nodal diaphragms, segments about as broad as long, filled with watery mucilage [656].

3.3.101.2 Habitat

Epiphytic on smaller algae in lower intertidal pools and sublittoral, South West England and Ireland, Channel Islands, locally common.

3.3.101.3 Distribution

Worldwide in tropical to subtropical and warmer seas with bordering warm-temperate zones.

3.3.101.4 Uses and Compounds

Extracts have anticoagulant [637], and antiherpetic [657] activity.

3.3.102 Chylocladia verticillata (Lightfoot) Bliding

3.3.102.1 Description

Soft, gelatinous, cylindrical, pinkish to brown-red fronds (often bleached yellow or almost white in sunny Habitats), to $300\mathrm{mm}$ high, filled with a watery mucilage. Main axis simple, jointed, with nodal diaphragms, very slightly constricted at nodes, $2$-several branches per node, themselves often branched, with small beaded ultimate ramuli. Very variable in branching pattern, plants of exposed coasts often simple with small terminal tufts of ramuli [658].

3.3.102.2 Habitat

On rocks and stones and epiphytic, lower intertidal and sublittoral, generally distributed, common.

3.3.102.3 Distribution

NE Atlantic (Norway to Sierra Leone); Mediterranean.

3.3.102.4 Uses and Compounds

Extracts have cytotoxic activity [659].

3.3.103 Lomentaria articulata (Hudson) Lyngbye

3.3.103.1 Description

A small (up to $20\mathrm{cm}$ tall, but usually much shorter) dark brown to red alga (Fig. 6.39). The thallus is conspicuously constricted giving a segmented appearance. Starting almost at the base, many branches grow out of each constriction, the bead-like segments becoming gradually smaller toward the tip of the branch. The plant is very shiny and the tips of branches may be bleached pink or orange [1].

Fig. 6.39

Underwater photo of Lomentaria articulata

3.3.103.2 Habitat

On rocks and stones in pools, lower intertidal and sublittoral, generally distributed, frequent.

3.3.103.3 Distribution

NE and E Atlantic (Scandinavia to Cameroon), Mediterranean, Black Sea, Indian Ocean (India), W Pacific (Philippines).

3.3.103.4 Uses and Compounds

Extracts have antioxidant [316], and antimicrobial [660] activity.

3.3.104 Rhodymenia pseudoplamata (J.V. Lamouroux) P.C. Silva

3.3.104.1 Description

Flattened, fan shaped, rather stiff, rose-red fronds, to $100\mathrm{mm}$ high, with long or short stipes arising from a discoidal base. Fronds repeatedly dichotomously lobed, axils wide, apices rounded, margin smooth [32].

3.3.104.2 Habitat

On rocks, shady pools lower intertidal and sublittoral, also epiphytic on L. hyperborea stipes.

3.3.104.3 Distribution

NE Atlantic (Scandinavia to Cap Verde Islands), E Atlantic (W Africa), SE Atlantic (Namibia, South Africa); NW Atlantic (N and S Carolina), Caribbean, SW Atlantic (Brazil, Uruguay); Mediterranean.

3.3.104.4 Uses and Compounds

Extracts have antibacterial activity [358].

3.4 Domain/Empire Eukaryota, Kingdom Chromista, Phylum Ochrophyta; Class Phaeophyceae (Brown Algae)

• Order: Cutleriales

3.4.1 Cutleria multifida (Turner) Greville

3.4.1.1 Description

Only the morphologically more conspicuous Cutleria-phase is described: thallus erect, light to yellow-brown, also olive-brown, flattened, membranous, with smooth margins, deeply incised and repeatedly irregular forking, with linear to wedge-shaped sections, gradually narrowing toward the tip and dissected apices, fringed by a tuft of hair-like filaments; without stipe, rhizoidal discoid holdfast [32].

3.4.1.2 Habitat

On rocks, usually isolated, sublittoral to $10\mathrm{m}$.

3.4.1.3 Distribution

NE Atlantic (Scandinavia to Canary Islands); Mediterranean; Indian Ocean; NW Pacific (Japan); SE Pacific (Chile); Pacific Islands; Australia.

3.4.1.4 Uses and Compounds

Extracts have anticoagulant activity [661].

3.4.2 Zanardinia typus (Nardo) P.C. Silva

3.4.2.1 Common Name

Penny weed.

3.4.2.2 Description

Z. typus is a fairly small brown seaweed with flat fronds that may be either round or fan-like and possibly irregular in shape. The appearance may change with age, varying in color from olive to dark brown or black and in texture from smooth to leathery. The edge of the fronds may be smooth or ruffled, and has a distinct fringe of hairs [662].

3.4.2.3 Habitat

Found mainly on silty boulders or bedrock, rarely on living substrata, on sublittoral from shallow water to about $20\mathrm{m}$ depth.

3.4.2.4 Distribution

NE Atlantic (SW Ireland and SW Britain, Canary Islands); Mediterranean (Italy).

3.4.2.5 Uses and Compounds

Extracts have antifouling [663], antioxidant [664], antibacterial and antifungal [311, 62, 665], antiviral cytotoxic, and antimitotic [507, 62].

• Order: Desmarestiales

3.4.3 Desmarestia aculeata (Linnaeus) J.V. Lamouroux

3.4.3.1 Description

This species of brown seaweed looks like a flattened cactus; a flat main axis approximately $2\mathrm{cm}$ wide with obvious midrib arises from a discoid holdfast. Numerous thinner opposite growing flat side branches are attached to the main axis. D. ligulata grows low to sublittoral and reaches $80\mathrm{cm}$ in length. Other species of flattened Desmarestia have been described for our area and there is ongoing discussion about the relationships of these species and their exact number. D. munda is described as growing to over $120\mathrm{cm}$ with side branches as wide as the main axis ($4$–$10\mathrm{cm}$), but strictly sublittoral. Beach Watchers have observed individuals that match both descriptions and a combination of the two [1].

3.4.3.2 Habitat

On rocks in pools in the lower intertidal; however, mostly sublittoral, to $15\mathrm{m}$ depth often abundant.

3.4.3.3 Distribution

NE Atlantic (Iceland to Morocco); NW Pacific (Japan); NE Pacific (Alaska to California); SE Pacific (Chile); Pacific Islands (Hawaii); Australia, New Zealand.

3.4.3.4 Uses and Compounds

Source of Laminaran and Alginic acid  [666].

3.4.4 Desmarestia ligulata (Stackhouse) J.V. Lamouroux

3.4.4.1 Description

This species of brown seaweed looks like a flattened cactus (Fig. 6.40); a flat main axis approximately $2\mathrm{cm}$ wide with obvious midrib arises from a discoid holdfast. Numerous thinner opposite growing flat side branches are attached to the main axis. D. ligulata grows low to sublittoral and reaches $80\mathrm{cm}$ in length. Other species of flattened Desmarestia have been described for our area and there is ongoing discussion about the relationships of these species and their exact number. D. munda is described as growing to over $120\mathrm{cm}$ with side branches as wide as the main axis ($4$–$10\mathrm{cm}$), but strictly sublittoral. Beach Watchers have observed individuals that match both descriptions and a combination of the two [1].

Fig. 6.40

Underwater photo of Desmarestia ligulata

3.4.4.2 Habitat

On rocks in pools in the lower intertidal; however, mostly sublittoral, to $15\mathrm{m}$ depth often abundant.

3.4.4.3 Distribution

NE Atlantic (Iceland to Morocco); NW Pacific (Japan); NE Pacific (Alaska to California); SE Pacific (Chile); Pacific Islands (Hawaii); Australia, New Zealand.

3.4.4.4 Uses and Compounds

The brown algae D. ligulata and D. viridis accumulate sulfuric acid until their average internal pH is $0.5$ – $0.8$. A related species, D. aculeata, does not accumulate acid [667]. Extracts have antimicrobial [668], antioxidant, and antitumor [316, 421] activity.

• Order: Dictyotales

3.4.5 Canistrocarpus cervicornis (Kützing) De Paula & De Clerck

3.4.5.1 Synonym

Dictyota cervicornis Kützing

3.4.5.2 Description

Thallus tufted, yellow-brown, erect, somewhat intertwined; branches screw-like twisted, narrow ribbons, mostly forking, but asymmetrically branching (one fork longer than the other), widening at the fork-base (to $4\mathrm{mm}$), the upper thallus parts narrow ($1$–$2\mathrm{mm}$ wide), slightly tapering upward, tips acute, margins smooth; anchored to right substrata by a discoidal holdfast [669].

3.4.5.3 Habitat

Grows on rocks and epiphytically in shallow water of warmer seas, but also in up to $20\mathrm{m}$ depth.

3.4.5.4 Distribution

Warm E Atlantic; Caribbean; SW Atlantic (Brazil); NW Pacific (Japan, China); Indian Ocean.

3.4.5.5 Uses and Compounds

Extracts have antisnake [670], antifouling [671], antifungal [204], antiproliferative [672], antiviral [673], antioxidant and anticoagulant [64, 674] activity.

3.4.6 Dictiopteris polypodioides (A.P. De Candolle) J.V. Lamouroux

3.4.6.1 Synonym

Dictyopteris membranacea (Stackhouse) Batters

3.4.6.2 Description

Thallus flat and leaf-like, to $300\mathrm{mm}$ long and $20$–$30\mathrm{mm}$ broad; fronds olive to yellow-brown, translucent, and$\pm$regularly dichotomously forked with a prominent midrib extending to the apices (Fig. 6.41). Margins sometimes split to the midrib. Initially with an unpleasant smell shortly after collection, and degenerating quickly [1].

Fig. 6.41

Herbarium specimen of Dictiopteris polypodioides (MACOI no. 260)

3.4.6.3 Habitat

In low-light calm water, to $40\mathrm{m}$ depth.

3.4.6.4 Distribution

Cold temperate to warm NE Atlantic (Ireland to Canary Islands); Mediterranean; W Pacific (Philippines); NW Pacific (Japan); Caribbean; Indian Ocean.

3.4.6.5 Uses and Compounds

Extracts have anti-inflammatory [675], antibacterial [276, 675], antitumor [676], antioxidant [675], and cytotoxic [62] activity.

3.4.7 Dictyopteris delicatula J.V. Lamouroux

3.4.7.1 Description

D. delicatula has erect, light-brown, strap-shaped blades attaching to substratum at basal holdfast or to adjacent branches, creating a tangled mass $2$–$8\mathrm{cm}$ in height. Dichotomous to irregularly branched bilayered blades, $0.5$–$5.0\mathrm{mm}$ wide, have a distinctly raised midrib that may be several cells thick. Cells of blades are arranged in parallel rows at acute angles to midrib. Scattered clusters of hyaline hairs in dense tufts arise along midrib on only one surface of midrib [677].

3.4.7.2 Habitat

Attached to rock-sand coral fragments, also as an epiphyte on larger seaweeds; from the lower sublittoral to $\approx 10$ – $30\mathrm{m}$ depth.

3.4.7.3 Distribution

Tropical and Sub-tropical Atlantic (Canary Islands), Gulf of Mexico, Caribbean, Indian Ocean, Red Sea, Central Pacific, Costa Rica; Pacific.

3.4.7.4 Uses and Compounds

Extracts have antifungal [204], cytotoxic [459], antibacterial [449], anti-proliferative and antitumor [672], antioxidant and anticoagulant [459, 678, 679] activity.

3.4.8 Dictyopteris plagiogramma (Montagne) Vickers

3.4.8.1 Common Name

Limu lipoa

3.4.8.2 Description

Thalli dark olivaceous green to light tan or almost yellowish, occurring as dense often intertwined tufts of multiple axes arising from a common matted holdfast; fronds $2$–$8\mathrm{cm}$ long, $1$–$8\mathrm{mm}$ wide, usually crisp in texture and pungently aromatic when fresh; branching of juvenile thalli basically dichotomous, becoming pseudomonopodial at maturity and then highly irregular as wing tissue wears away to leave midribs as several orders of stalks. Blades from apex to base traversed from midrib to margin by regularly spaced microscopic to faintly visible veins that arise at angles of $10$–${20}^{\circ }$ and form broad arches bending away from the apices [680].

3.4.8.3 Habitat

Uncommon, on hard substrates, often attached to coral fragments or scattered rocks on deep sand plains; $9$–$55\mathrm{m}$ deep.

3.4.8.4 Distribution

Widespread in the subtropical to tropical waters of the Atlantic, Caribbean, Mediterranean, Indian Oceans, and in the Pacific Ocean.

3.4.8.5 Uses and Compounds

Produces Laminaran and Alginic acid and is used as food [681]. Extracts have antioxidant activity [682].

3.4.9 Dictyota ciliolata Sonder ex Kützing

3.4.9.1 Description

Thallus erect, light brown with yellow green iridescence, sometimes with dark brown striations; branching irregular to dichotomous; branches strap-shaped, margin with teeth, often spirally twisted; medullary cells one layer thick, rectangular [683].

3.4.9.2 Habitat

Attached to rock in seagrass bed, and in intertidal pools in moderately high energy Habitats.

3.4.9.3 Distribution

Warm E Atlantic (Madeira, Canary Islands, W Africa); Caribbean; SW Atlantic (Brazil); SW Pacific; Indian Ocean; Australia.

3.4.9.4 Uses and Compounds

Extracts have antifungal [204], and antioxidant [65] activity.

3.4.10 Dictyota dichotoma (Hudson) J.V. Lamouroux

3.4.10.1 Description

Thallus flat, homogenous yellow-brown to darker brown, with fairly regular dichotomous branches (Fig. 6.42) with parallel sides to $30\mathrm{cm}$ long, the tips usually bifid; branches $3$ to $12\mathrm{mm}$ wide, membranous, without a mid-rib [1].

Fig. 6.42

Underwater photo of Dictyota dichotoma

3.4.10.2 Habitat

In shallow water on firm substrata, found in $>$ $50\mathrm{m}$ depth.

3.4.10.3 Distribution

Common and globally distributed.

3.4.10.4 Uses and Compounds

A chlorine-containing perhydroazulene diterpene, dictyol J $146$, was isolated from the brown alga D. dichotoma along with two known diterpenes, dictyolactone and sanadaol [684, 685]. All three metabolites were algicidal [686] to the bloom-forming species Heterosigma akashiwo and Karenia mikimotoi. Dictyolactone also displayed a moderate activity against the dinoflagellate Alexandrium catenella.

Extracts of this seaweed have also anticoagulant [512, 637, 687], cytotoxic [62, 688, 689], antitumor [126, 690], anti-inflammatory [691], antifungal [62], larvicidal [51], antimicrobial [18, 40, 692], and antifouling [693, 694] activity. Extracts have also used for a liquid fertilizer [695].

3.4.11 Dictyota fascida (Roth) J.V. Lamouroux

3.4.11.1 Synonym

Dilophus fasciola (Roth) M.A. Howe

3.4.11.2 Description

D. fasciola has a ribbon-like opaque thallus with a height of $100$–$150\mathrm{mm}$, and width of $1$–$6\mathrm{mm}$. The thalli are flattened, and highly branched in a  dichotomous pattern; it is three cells thick and without midrib. The branches are attenuated with forked tips; it has a yellowish-brown coloration [696].

3.4.11.3 Habitat

On firm substrata in the intertidal.

3.4.11.4 Distribution

Warmer E Atlantic (Madeira, Canary Islands); E Africa); Mediterranean; Indian Ocean.

3.4.11.5 Uses and Compounds

Extracts have antimicrobial [130], antioxidant [664], and antifouling [697] activity.

3.4.12 Dictyota implexa (Desfontaines) J.V. Lamouroux

Synonyms: Dictyota dichotoma var. implexa (Desfontaines) S.F. Gray; Dictyota linearis (C. Agardh) Greville

3.4.12.1 Description

Thallus bushy, brown, consisting of intertwined, erect fascicles; thallus regularly forking, width at the base $2$–$3\mathrm{mm}$, abruptly narrowing toward the tipe, then filamentous ($<0.5\mathrm{mm}$) [32].

3.4.12.2 Habitat

From $0$ to $10\mathrm{m}$ depth.

3.4.12.3 Distribution

Atlantic Islands (Azores and Canary Islands); Mediterranean.

3.4.12.4 Uses and Compounds

Extracts have antibacterial [276, 40, 698], antifungal [276], and antioxidant [112] activity.

3.4.13 Dictyota mertensii (Martius) Kützing

3.4.13.1 Description

Thallus bushy, brown, often iridescent blue-green under water, erect, robust and stately; the flattened fronds show a branching pattern atypical for the genus: distinct main axes branch repeated-alterning, terminal forkings of the latitudinal axes turn into spur-like, $1$–$2\mathrm{mm}$ long, pointed or rounded tips [32].

3.4.13.2 Habitat

On rocks in shallow (about $2\mathrm{m}$ deep) water, in moderately wave-exposed sites in the intertidal, also in up to approx. $15\mathrm{m}$ depth.

3.4.13.3 Distribution

Warm E Atlantic (Canary Islands to Gabon); Caribbean; SW Pacific and Pacific Islands.

3.4.13.4 Uses and Compounds

Extracts have antibacterial [699] and feeding-deterrent [700, 701] activity.

3.4.14 Dictyota spiralis Montagne

3.4.14.1 Synonym

Dilophus spiralis (Montagne) G. Hamel

3.4.14.2 Description

Thallus bushy, erect; lamina segments ribbon-like, regular forking, spiralling around the longitudinal axis, tips straight, pointed. $10$–$20\mathrm{cm}$ long, brown, tips a lighter shade [702].

3.4.14.3 Habitat

Near the surface on rocks, also as an epiphyte.

3.4.14.4 Distribution

NE Atlantic (W Ireland and SW Britain to Mauretania); Mediterranean.

3.4.14.5 Uses and Compounds

Extracts have antimicrobial activity [130, 18, 703].

3.4.15 Lobophora variegata (J.V. Lamouroux) Womersley ex E.C. Oliveira

3.4.15.1 Description

These algae occur in orange brown to dark brown in colour and bear a leathery feel. The blades may appear as fan shaped, flabellate or as crusts. They are often tightly adhered to the substrate [704].

3.4.15.2 Habitat

Grow in most reef environments, encrusting great areas of shaded, rocky substrates. Especially abundant on undercut wall faces along deep drop-offs.

3.4.15.3 Distribution

Warm E Atlantic (Madeira, Canary Islands, W Africa); Caribbean (Trinidad); Hawaii; Indian Ocean, Australia.

3.4.15.4 Uses and Compounds

Lobophorolide was isolated from the common brown alga L. variegata and displayed a  potent and highly specific activity against the marine filamentous fungi Dendroyphiella salina and Lindra thalassiae and a potent activity against C. albicans and antineoplastic [705]. Extracts have also antiprotozoal [706, 707], antimicrobial [260, 65, 707], anti-inflammatory [708], hypoglycemic [81], antifungal [61, 62], antifouling [260], anti-inflammatory, antioxidant, and anticoagulant [65, 709, 710] activity.

3.4.16 Padina gymnospora (Kützing) Sonder

3.4.16.1 Description

Usually the blades are $10$–$12\mathrm{cm}$ long and broad, but plants with $15\mathrm{cm}$ long and to $20\mathrm{cm}$ broad blades may be found; the frond has three layers of cells except near the enrolled edge where two cell layers occur; the hair lines alternate on both sides of the blade and the dark lines of sporangia are found just above every second hair-line; plants tufted, $5$–$10\mathrm{cm}$ tall, the blades $5$–$20\mathrm{cm}$ broad rounded or split into narrower portions, the lower parts stalk like and stupose, usually rather moderately calcified on the upper surface [711, 712].

3.4.16.2 Habitat

On rocks and other firm substrata (mangrove-roots), in calm or only moderately wave-exposed locations in the intertidal, found in up to $14\mathrm{m}$ depth.

3.4.16.3 Distribution

Warm E and SE Atlantic (Canary Islands to Angola); SW Atlantic (Brazil); Caribbean; W Pacific and Indo-Pacific (Philippines, Vietnam); Pacific Islands; Indian Ocean; Australia.

3.4.16.4 Uses and Compounds

Extracts have anti-inflammatory [713], antibacterial [114, 493, 714, 715], antifungal [715], anticoagulant [716], antioxidant [717], neuroprotective [718], antiviral [172, 719] activity.

3.4.17 Padina pavonica (Linnaeus) Thivy

3.4.17.1 Common Name

Peacock’s tail

3.4.17.2 Description

The fronds are thin and leafy, flattish and entire when young, but often concave, or almost funnel shaped in mature specimens, with a lactiniate or irregularly lobed margin (Fig. 6.43). The inner (or upper) surface is covered in a thin coating of slime, and the outer (or lower) surface is banded with zones of light brown, dark brown, and olive green. Small, fine hairs form concentric lines, $3$–$5\mathrm{mm}$ apart, from the outer margin continuing down the outer (colored) surface of the fronds [32].

3.4.17.3 Habitat

On rocks in sheltered locations near the surface, to $20\mathrm{m}$ depth.

3.4.17.4 Distribution

NE Atlantic (S Britain to Canary Islands, W Africa); Mediterranean; Caribbean; W Pacific (Philippines), Pacific Islands; Indian Ocean.

3.4.17.5 Uses and Compounds

Cosmetic uses for skin antiaging [720]. High anticoagulant activity has been reported for purified fucan sulphates from P. pavonica (xylofucomannoglucuronan) [721]. Extracts have also allelopathic [722], antifungal [204, 286, 438, 722], antibacterial [284, 421, 72, 723, 724], anticoagulant [512], antitumor [126, 421], antiviral [72], cytotoxic, and antimitotic [62, 72, 725] activity.

Fig. 6.43

Padina pavonica specimens

3.4.18 Taonia atomaria (Woodward) J. Agardh

3.4.18.1 Description

Thallus erect, flat ribbon-shaped, paper-like thin, irregularly branching into wedge-shaped segments and/or deeply dividing into narrower, almost linear bands, the upper margin appearing frayed; without midrib; dark, slightly undulating zones of transverse stripes on both sides (hairs and reproductive structures). Stipe-like at the bottom anchored by a dense rhizoidal felt [32].

3.4.18.2 Habitat

In pools on rocky and sandy substrata in semiwave-exposed situations up to $10\mathrm{m}$ depth.

3.4.18.3 Distribution

NE Atlantic (Britain to Mauretania), Mediterranean.

3.4.18.4 Uses and Compounds

Used as functional foods ingredient [205, 726, 727].

T. atomaria was a source of meroditerpenes atomarianones A $123$ and B $124$, the cytotoxic agents against the GlossaryTerm

NSCLC

-N6 and A-549 cell lines [728]. The brown alga T. atomaria was also a source of meroditerpenes atomarianones, the cytotoxic agents against some cell lines [728].

Sargaquinone were isolated from the brown alga T. atomaria and were anti-inflammatory agents by inhibition of leukotriene biosynthesis [729].

Extracts have also antioxidant [102, 205, 685], antitumor [730], and antimicrobial [130] activity.

3.4.19 Zonaria tournefortii (J.V. Lamouroux) Montagne

3.4.19.1 Description

Thallus erect, with flat lobed sections divided into. Wedge-shaped segments, often incised and proliferating; lamina inconspicuously banded by distant, concentric rows of hairs which are parallel to the distal margin; additionally, delicate lines which run radially from the base to the upper margin; margins not enrolled, lamina not calcified; basally thickened, stipe-like, branching, stipe extending like a midrib into the segments; cushion-like rhizoidal network [32].

3.4.19.2 Habitat

In shady locations, from the surface to $40\mathrm{m}$ depth.

3.4.19.3 Distribution

Warm NE Atlantic (Madeira, Canary Islands, W Africa); Mediterranean; Caribbean; SW Atlantic (Brazil); SW Indian Ocean (South Africa).

3.4.19.4 Uses and Compounds

Extracts have antibacterial activity [391].

• Order: Ectocarpales

3.4.20 Asperococcus bullosus J.V. Lamouroux

Description: Thallus simple, membranous, hollow and irregularly bladder-like bloated; with short stipe which abruptly widens into the hollow inflated thallus body; reproductive structures on the surface are visible as dark dots; discoid holdfast [32].

3.4.20.1 Habitat

Lower intertidal and shallow sublittoral; mainly epiphytic.

3.4.20.2 Distribution

Widely distributed in temperate seas.

3.4.20.3 Uses and Compounds

Extracts have antioxidant and antitumor activity [205, 731].

3.4.21 Chordaria flagelliformis (O.F. Müller) C. Agardh

3.4.21.1 Common Name

Black whip weed.

3.4.21.2 Description

Thallus string-like, with divaricated branches, slippery, solid, dark brown to black, $10$–$30\mathrm{cm}$ high; branching irregular, alternate from all sides; branches cylindrical, or slightly compressed, to $3\mathrm{mm}$ wide, slightly tapering toward the base. Branch apices blunt. Medulla composed of longitudinal filaments of long cylindrical cells to $50$–$600\mathrm{\mu }\mathrm{m}$ decreasing toward periphery to $16$–$18\mathrm{\mu }\mathrm{m}$. A layer of assimilative unbranched filaments (of $4$–$9$ cell rows) develop from the peripheral cells [732].

3.4.21.3 Habitat

Growing on stony bottom, in low intertidal to sublittoral, in calm shores and exposed to wave action.

3.4.21.4 Distribution

NE Atlantic (from Greenland, Scandinavia to Britain, North Sea and Baltic)); NW Atlantic; SE Atlantic; NE Pacific; Antarctica and Sub-Antarctic Islands.

3.4.21.5 Uses and Compounds

Used as food [546, 732], and extracts have antitumor [733], anticoagulant and antithrombotic [732, 734], and antioxidant [546] activity.

3.4.22 Colpomenia peregrina Sauvageau

3.4.22.1 Common Name

Oyster thief.

3.4.22.2 Description

Sometimes regularly spherical (C. peregrina) or more or less irregular outline (C. sinuosa), yellowish-brown color, fixed to the substrate by filamentous rhizoids. Internally, the thallus is characterized by an outer cortex composed of small colored cells and inner pith composed of large pigmented cells [1].

3.4.22.3 Habitat

On moderately wave-exposed rocks and (mostly) on other algae in the lower intertidal.

3.4.22.4 Distribution

NE Atlantic (Norway to Canary Islands); W Mediterranean; NW Pacific (Japan); NE Pacific (Alaska to California); Australia, New Zealand.

3.4.22.5 Uses and Compounds

Extracts have cytotoxic and antibacterial activity [735].

3.4.23 Colpomenia sinuosa (Mertens ex Roth) Derbès & Solier

3.4.23.1 Description

Thallus bladder-like, smooth, slick, hollow, crisp, spherical to sac-like, irregularly expanded or somewhat lobed, to $30\mathrm{cm}$ diameter, $10\mathrm{cm}$ high, golden-brown (Fig. 6.44); often covered with fine colorless hairs; reproductive sori as dark raised patches on surface. Membrane $300$–$500\mathrm{\mu }\mathrm{m}$ thick, of $4$–$6$ cell layers; medullary cells to $240\mathrm{\mu }\mathrm{m}$ diameter; cortex $1$–$2$ cells thick; surface cells $3.7$–$8.0$ $(-16)\mathrm{\mu }\mathrm{m}$ diameter, darkly pigmented; surface-phaeophycean-hairs transparent, in scattered clusters; holdfast not apparent, attachment at many points [1].

Fig. 6.44

Underwater photo of Colpomenia sinuosa

3.4.23.2 Habitat

Firmly attached to hard surfaces or epiphytic on other organisms; lower intertidal to $15\mathrm{m}$ deep.

3.4.23.3 Distribution

NE Atlantic (Portugal to Canary Islands); Mediterranean; E and SE Atlantic (W to South Africa); Caribbean; SW Atlantic (Brazil, Uruguay); Indian Ocean; NW Pacific (Japan, China) NE Pacific (California); SE Pacific (Galapagos, Chile); W Pacific and Indo-Pacific (Vietnam, Malaysia, Philippines); Pacific Islands (Hawaii, Polynesia); Australia, New Zealand.

3.4.23.4 Uses and Compounds

Edible, used as food [32], fertilizer, and source of alginic acid [109]. Extracts have antibacterial [228, 692, 86], antifungal [204], antioxidant [736, 737], antitumor [126], antileukemic, antiprotozoan, and hypolipidemic [698] activity.

3.4.24 Ectocarpus siliculosus (Dillwyn) Lyngbye

3.4.24.1 Description

Plants tufted, often only one to a few cm tall, but in exceptional cases up to $20\mathrm{cm}$. Axes freely branched, main axis not distinguishable; filaments up to $30\mathrm{\mu }\mathrm{m}$ in diameter, tapering toward the apices. Sometimes forming terminal pseudohairs, forms soft beards on larger plants or other firm substrata, and grows up to $2$ feet long [738].

3.4.24.2 Habitat

On various firm substrata near the low-tide mark or below, later often free floating; also epiphytic.

3.4.24.3 Distribution

Almost globally distributed: NE Atlantic (Greenland to Canary Islands; North Sea; Baltic); Mediterranean; NW Atlantic (Canada, USA); SE and SW Atlantic; Caribbean; NW Pacific (Japan, China); NE Pacific, Australia and New Zealand; Sub-Antarctica.

3.4.24.4 Uses and Compounds

Extracts have antibacterial [248, 276, 454], and antioxidant [595] activity.

3.4.25 Hydroclathrus clathratus (C. Agardh) M.A. Howe

3.4.25.1 Common Name

Perforated brown seaweed.

3.4.25.2 Description

H. clathratus is a very interesting brown seaweed, appearing as a $6$ – $10\mathrm{cm}$ yellow-brown clump of very porus, chain-like tissue. The plant has a very open, sponge-like structure with a complex series of holes perforating narrow, fleshy strips. Its name, clathratus, means latticed, an apt description. H. clathratus is found worldwide in warm seas but is an uncommon species on hard reefs. H. clathratus is more often found on in calm, shallow areas where it is anchored in bare sand [32, 739].

3.4.25.3 Habitat

In mid-littoral, often on wave-exposed rocks, more rarely in depths of apertures $1$–$3\mathrm{cm}$, of the bridges $1$–$3\mathrm{mm}$.

3.4.25.4 Distribution

The worldwide distribution of H. clathratus includes Europe, both coasts of Africa, the Pacific Islands, Asia, Australia, North and South America from California through Chile and the Gulf of Mexico.

3.4.25.5 Uses and Compounds

H. clathratus has been used for centuries in traditional cuisine and medicine of island cultures, such as Hawaii. Hydroclathrus clathratus is known to possess anticancer, anti-herpetic, anti-inflammatory, and anticoagulant properties and is now used as a mineral supplement in cosmetics and as a soil-additive (fertilizer) for its high concentration of micronutrients [32, 739].

Extracts have antiviral [740, 741], antitumor [742, 743, 744, 745, 746, 747], cytotoxic and antiviral [72], and antimicrobial [230, 248, 692, 715, 72] activity.

3.4.26 Leathesia marina (Lyngbye) Decaisne

3.4.26.1 Synonym

Leathesia difformis

3.4.26.2 Common Names

Sea cauliflower, Sea balls.

3.4.26.3 Description

Thallus round in young stages, light brown, firm-fleshy and slimy-smooth, later hollow, and with an irregularly convoluted surface [32].

3.4.26.4 Habitat

Mostly epiphytically on larger algae or sessile on rocks.

3.4.26.5 Distribution

Nearly worldwide; NE Atlantic (Iceland to Canary Islands); Mediterranean; NW Atlantic; SE Atlantic (Namibia, South Africa); Indian Ocean (South Africa); NW Pacific (Japan, China); NE Pacific (Alaska to California); SW Pacific (Philippines); Australia; New Zealand, Antarctica and Sub-Antarctica.

3.4.26.6 Uses and Compounds

Extracts have agricultural bio-control and bio-stimulating [748], antifouling [749], antiviral [750], antioxidant [111], and antitumor [751] activity.

3.4.27 Petalonia fascia (O.F. Müller) Kuntze

3.4.27.1 Description

Thallus consists of erect, light to dark brown, dorsoventrally flattened lamina, arising from a  holdfast singly or in clusters; linear or broadly lanceolate to almost elliptical, abruptly or gradually narrowing toward the base and merging into a elliptical, abruptly or gradually narrowing toward the base and merging into a short stipe, only slightly narrowing at the tip, rounded and often frayed; thallus undivided, membranous and thin when young, later leathery-tough with smooth, sometimes undulating, margins (Fig. 6.45). The species is very polymorphic especially in relation to thallus width [752].

Fig. 6.45

Herbarium specimen of Petalonia fascia (MACOI no. 292)

3.4.27.2 Habitat

Found growing on rock in the mid intertidal to shallow sublittoral from protected to semiexposed Habitats.

3.4.27.3 Distribution

N NE Atlantic (Greenland to Canary Islands); Mediterranean; NW Atlantic (Arctic to New Jersey; SE Atlantic (Senegal, Namibia, South Africa); SW Atlantic (Brazil, Uruguay); Indian Ocean (Pakistan, South Africa); NW Pacific (Japan, China); NE Pacific (Alaska to California); SE pacific (Chile); Australia, New Zealand; Antarctica, and Sub-Antarctica.

3.4.27.4 Uses and Compounds

Used as directly food, and the extracts have antimicrobial and antioxidant [203, 698] activity.

3.4.28 Punctaria latifolia Greville

3.4.28.1 Description

Frond oblong or obovate, medium brown, complanate, simple, ovate to ligulate, thickish, gelatinous and tender, usually $5$–$20$ $(-30)\mathrm{cm}$ long and $(1-)$ $2$–$6\mathrm{cm}$ broad, margin smooth to undulate, with a short, slender, stipe and cuneate base, arising from a small, discoid, rhizoidal holdfast $(0.5-)$ $1$–$2$ $(-3)\mathrm{mm}$ across; epiphytic (usually on Posidonia or Heterozostera) or epilithic; growth diffuse. Structure $(2-)$ $4$–$6$ cells and $80$–$120\mathrm{\mu }\mathrm{m}$ thick, with a medulla $2$–$4$ cells thick with few phaeoplasts, and a monostromatic cortex of isodiametric cells mostly of similar size to the medullary cells, $15$–$25\mathrm{\mu }\mathrm{m}$ across in surface view, each with several discoid to irregularly shaped phaeoplasts each with a pyrenoid; phaeophycean hairs scattered, single or in small groups, $7$–$10\mathrm{\mu }\mathrm{m}$ in diameter [753].

3.4.28.2 Habitat

On rocks in the upper intertidal down to several meters depth.

3.4.28.3 Distribution

Widely distributed in cooler temperate waters.

3.4.28.4 Uses and Compounds

Extracts have antibacterial [735], antiviral [735], cytotoxic, and antitumor [102, 735, 751, 754] activity.

3.4.29 Scytosiphon lomentaria (Lyngbye) Link

3.4.29.1 Common Name

Sausage weed

3.4.29.2 Description

S. lomentaria has cylindrical, shiny, olive brown, unbranched fronds up to $400\mathrm{mm}$ long. They have short stalks and a large number may arise from a single discoid holdfast. They widen to $3$–$10\mathrm{mm}$ and narrow again near the tip. They are hollow and often have irregular constrictions [755].

3.4.29.3 Habitat

It occurs in the littoral zone on wave-exposed shores and rock pools. Small plants are often found growing on limpets and pebbles.

3.4.29.4 Distribution

Cosmopolitan in temperate and cold seas.

3.4.29.5 Uses and Compounds

Used directly as food, and the extracts have antioxidant [111, 112, 335, 756, 757], antiviral [278], antimicrobial [421, 698], antitumor [421, 758], and antifouling [759] activity.

• Order: Fucales

3.4.30 Ascophyllum nodosum (Linnaeus) Le Jolis

3.4.30.1 Common Names

Knotted wrack, Asco, Sea Whistle, Bladderwrack, Egg wrack.

3.4.30.2 Description

A. nodosum is a perennial brown intertidal seaweed species most abundant on sheltered rocky shores in the mid-intertidal zone of the North Atlantic. Olive green in color, A. nodosum generally grows upward in the water column anchoring to hard substrates using a disk-shaped holdfast (Fig. 6.46). A single specimen resembles an intertwined mass of shoots and branches. Incoming tides gradually refloat vast stands of A. nodosum, until it becomes an expansive swaying undersea forest. Its thallus can measure from $30$ to $60\mathrm{cm}$, and is flexible to decrease breakage that may result from strong wave action. Its long, thick, leathery, branching strap-like fronds are typically between $0.5$ and $2\mathrm{m}$ in length, and have large egg-shaped air bladders (pneumatocysts) at regular intervals along their length which keep the plant floating upright when submerged at high tide, and hang downward, draping over intertidal rocks in a thick, tangled, and glistening mat at low tide. The large air bladders take it toward the light for maximum photosynthesis. The fronds have no midrib.

Fig. 6.46

A. nodosum specimen

It is present and grows all year round, and has no resting period. The species grows slowly and can live to be several decades old in wave-sheltered locations of temperate waters, and it has the capability to survive low temperatures. It can eventually grow to three and four meters; individual fronds can become up to $15$ years old before breakage. The holdfasts of A. nodosum are thought to persist for several decades from which new fronds regenerate. Another interesting attribute of A. nodosum is that it repeatedly sloughs its entire outer epidermis, a phenomenon not exhibited by other related seaweeds.

A. nodosum attaches to rocks and boulders on the middle shore in a range of habitats, from estuaries to relatively exposed coasts. These sites can have low, moderate, and high wave action across low-, mid- and upper littoral heights, although some sublittoral populations have been reported. The upper limits of A. nodosum distribution are controlled by its ability to resist desiccation and high temperatures [1, 760].

3.4.30.3 Habitat

On rocks in sheltered locations of the mid- to the lower littoral zone.

3.4.30.4 Distribution

Distribution is confined to the North Atlantic basin, found in the Arctic Ocean, Baltic Sea, Belt Sea, Northern Europe, Gulf of Maine, North Sea, and Northwest Atlantic. Its northern limits are northern Norway and the White Sea in the east, and Baffin Island in the west. Southern distributions extend to northern Portugal and New Jersey.

3.4.30.5 Uses and Compounds

A. nodosum is very effective at accumulating nutrients and minerals from the surrounding seawater, and this is what makes them a valuable resource for human enterprise. This species is harvested for use in items such as food, fertilizer, soil conditioners, animal feed, skin and hair care products, cleaners, degreasers, equestrian products, and nutritional supplements. It is also popular in cosmetology and thalassotherapy. The Industry has more than $200$ product types from over $100$ companies which include A. nodosum as an ingredient [3, 4, 760].

Extracts of this species have anticoagulant [761], antiviral, and anti-inflammatory [762, 763], antibacterial [764, 765], antioxidant [763, 766], nematicidal [767], agricultural biostimulant [768], antitumor [432], antifouling [61], and phytobiotic [769] activity.

3.4.31 Bifurcaria bifurcata R. Ross

3.4.31.1 Common Names

Brown tuning fork weed, Brown forking weed

3.4.31.2 Description

Up to $30\mathrm{cm}$ in length; olive-yellow in color, but much darker when dry (Fig. 6.47); holdfast expanded and knobby; frond cylindrical, unbranched near base then branching dichotomously. Elongate reproductive bodies present at ends of branches. Rounded air bladders sometimes present [1].

Fig. 6.47

Bifurcaria bifurcata specimen

3.4.31.3 Habitat

Epilithic in intertidal tide pools, occasionally exposed at low tide and extending into the shallow sublittoral.

3.4.31.4 Distribution

Temperate NE Atlantic (from W Ireland to Morocco).

3.4.31.5 Uses and Compounds

A linear cytotoxic diterpene bifurcadiol was isolated from the brown alga B. bifurcata by Di Guardia etal [770] which exhibit cytotoxicity against cultured human tumor cell lines. Extracts have also antifouling [771, 772], antibacterial [269, 773, 96], antiprotozoal [525], antioxidant [429, 731], and antitumoral [774] activity.

3.4.32 Cystoseira abies-marina (S.G. Gmelin)

3.4.32.1 Description

At the base a branching, gnarled stem with teeth-like appendages. Upper thallus tufted, forking or lateral branching at more or less the same length, single branches thin, covered with scattered dark dots, and conspicuous bilateral saw-teeth-like; conceptacles as wart-like swellings in the upper parts of the thallus; without swim bladders [32].

3.4.32.2 Habitat

It is mostly present in the Macronesian islands. Widely spread out in the sublittoral zone, in places subject to wave action.

3.4.32.3 Distribution

E Atlantic (Azores, Madeira, Canary Islands, Cap Verde Islands); Mediterranean (Spain, Sardinia, Libya, Italy).

3.4.32.4 Uses and Compounds

This species is used directly for food and as fertilizer [775]. Extracts have antioxidant [225, 776, 777], antimicrobial [778], and cytotoxic [225] activity.

3.4.33 Cystoseira baccata (S.G. Gmelin) P.C. Silva

3.4.33.1 Common Name

Bushy berry wrack

3.4.33.2 Description

Fronds usually solitary, $1\mathrm{m}$ or more in length, attached by a thick, conical attaching disk (Fig. 6.48). Axis simple or branched, up to $1\mathrm{m}$ in length, flattened, about $1\times 0.4\mathrm{cm}$ in transverse section; apex smooth and surrounded during periods of active growth by incurred young laterals. Lateral branch systems distichous, alternate, radially symmetrical, and profusely branched in a repeatedly pinnate fashion and bearing sparse, filiform, occasionally bifurcate appendages on the branches of higher orders; deciduous, leaving decurrent bases which give an irregular, zigzag outline to the axis. Aerocysts present in axes of branches of higher order, sometimes in chains; seasonal, particularly numerous in Autumn. Receptacles $1$–$5\mathrm{cm}$ long, formed from axes of ultimate ramuli, irregularly nodose and bearing simple, filiform appendages [779].

3.4.33.3 Habitat

Lower intertidal in large sandy pools or lagoons, mostly in persistent stands.

3.4.33.4 Distribution

Widely distributed in the NE Atlantic (Baltic, Netherlands, Belgium, Ireland, Britain, N France, N Spain, Portugal, Mauretania, and Canary Islands).

3.4.33.5 Uses and Compounds

Extracts have antifouling [780], antibiotic [781, 782], antiplasmodial, and cytotoxic [783] activity.

Fig. 6.48

Underwater photo of Cystoseira baccata

3.4.34 Cystoseira barbata (Stackhouse) C. Agardh

3.4.34.1 Description

The thallus is $15$–$20\mathrm{cm}$ tall-each branch ends with a conic foot (sole); in most cases the basement branches are joined together in a common base. The stem is narrow enough, $3$–$5\mathrm{mm}$ thick, cylindrical, the final side is smooth and unequal. The main branches are alternatively or chaotically branched from the stem, very long, cylindrical shape, plenty of small branches whose number gradually decreases, leaving a few singular cylindrical small branches, much shorter than the initial ones; the small branches are uniformly distributed along the main branches or come together as brooms nearest their tops. In winter and spring, there are many (air) bladders on branches. Cryptostoma are numerous on the surface of the branches and (air) bladders. The receptacles are spare shaded or cylindrical $0.2$–$1\mathrm{cm}$ long, strongly stressed on the scaphidia surface and with thready sterile tops; gathered in dense installments on the lateral surface of the branches: often in the receptacles the (air) bladders are metamorphosed and are distributed close the top branches [784].

3.4.34.2 Habitat

Rocky bottoms on pebbly grounds in sublittoral areas at $0.5$–$10\mathrm{m}$ depths.

3.4.34.3 Distribution

NE Atlantic (France to Portugal); Mediterranean, India and Russia.

3.4.34.4 Uses and Compounds

Source of alginic acid and the extracts have antioxidant, antibacterial, antifungal, anti-HIV, and hypoglycemic activity [130, 192, 201, 784, 785, 786, 787, 788].

3.4.35 Cystoseira brachycarpa J. Agardh

3.4.35.1 Synonym

Cystoseira balearica Sauvageau

3.4.35.2 Description

Plant caespitose, to $20$–$25\mathrm{cm}$ in height, attached to the substratum by a more or less compact discoid base formed of haptera; axes numerous, $2$ –$6$ with $8\mathrm{cm}$ high; apices of the axes not very prominent, flattened and smooth; tophules absent. Primary branches cylindrical, seasonally either with smooth bases or covered with small spinose; conical appendages, some of witch can give rise to smaller branches; secondary and tertiary branches also cylindrical and covered with spinose appendages [789].

3.4.35.3 Habitat

Occurs in the upper sublittoral zone, from the surface to several meters depth, in moderately exposed and high light-intensity places.

3.4.35.4 Distribution

Mediterranean.

3.4.35.5 Uses and Compounds

The linear diterpenes eleganolone and elegandiol, isolated from C. brachycarpa, inhibit contractile activities of acetylcholine and histamine on ileum musculature of guinea pigs [790, 791]. Extracts have antimicrobial and antiviral [136, 62, 792, 793], antifungal, cytotoxic, and antimitotic [62] activity.

3.4.36 Cystoseira compressa (Esper) Gerloff & Nizamuddin

3.4.36.1 Description

C. compressa has a discoid base with several spined axes; the axes have denticulate margins. It is irregularly branched with compressed primary ramifications, and compact crawling receptacles; the axes have a  height of $10$–$100\mathrm{mm}$, and a thickness of $2$–$5\mathrm{mm}$. This alga lacks any leaves, tophules, and air vesicles; C. compressa has an olive-brown coloration [794].

3.4.36.2 Habitat

On rocky substrata, especially in the shallow sublittoral of light exposed, sheltered locations, to $30\mathrm{m}$ depth.

3.4.36.3 Distribution

NE Atlantic (Azores, Canary Islands); Mediterranean.

3.4.36.4 Uses and Compounds

Extracts have anti-inflammatory and antiproliferative [795], antimicrobial [248, 72], antiviral, and cytotoxic [72] activity.

3.4.37 Cystoseira crinita Duby

3.4.37.1 Description

C. crinita has an upright, bushy thallus with smooth axes; it reaches a height of $50$–$350\mathrm{mm}$, and a width of $200$–$500\mathrm{mm}$. The main branches are rough, thin, and alternate; the upper section is particularly densely branched. The secondary ramifications are lacking spines, and the terminal receptacles are long, and compact. This alga lacks tophules and the gas vacuoles are either missing or few. C. crinita has a light-brown to blackish coloration [796].

3.4.37.2 Habitat

Rocky bottoms on pebbly grounds in sublittoral areas.

3.4.37.3 Distribution

Mediterranean.

3.4.37.4 Uses and Compounds

Extracts have antibacterial [114, 474, 735], antioxidant [717, 797, 798], antiviral and cytotoxic [735], anti-inflammatory, and antiproliferative [798] activity.

3.4.38 Cystoseira foeniculacea (Linnaeus) Greville

3.4.38.1 Description

Plant caespitose, to $30\mathrm{cm}$, attached to the substratum by a wide and irregular basal disk. Axes to $10\mathrm{cm}$ high, with a circular cross-section (to $5\mathrm{mm}$), normally spinose and with small scars from dehisced primary branches; apices of the axes not very prominent, with small spines [799].

3.4.38.2 Habitat

Occurs in mid-littoral pools and sheltered places.

3.4.38.3 Distribution

NE Atlantic (Scotland and Ireland to Senegal, Cap Verde Islands); Mediterranean.

3.4.38.4 Uses and Compounds

Extracts have antibacterial activity [60].

3.4.39 Cystoseira humilis Schousboe ex Kützing

3.4.39.1 Description

Characterized by highly differentiated basal and apical regions and the presence of catenate pneumatocysts (air vesicles). In old plants they have an elongated main axis, and in time the primary laterals become proportionally elongated. Their lower parts are strongly flattened into foliar expansions or basal leaves. Fertile regions which bear conceptacles are known as receptacles. These are normally found at the tips of the branches. Their basal and apical regions are highly differentiated. They have catenated pnuematocysts (air vesicles). The aerocyst or air vesicles keep the organism erect, by causing it to float in strong currents [800].

3.4.39.2 Habitat

Occurs in mid-littoral pools and sheltered places.

3.4.39.3 Distribution

One of the most widely distributed genera of the Fucales order and provides an essential habitat for many epiphytes, invertebrates, and fish. Found mostly in temperate regions of the Northern Hemisphere, such as the Atlantic, Mediterranean, Indian, and Pacific Oceans.

3.4.39.4 Uses and Compounds

Extracts have antibacterial activity [171, 269, 96].

3.4.40 Cystoseira mediterranea Sauvageau

3.4.40.1 Description

C. mediterranea has an upright thallus, with a single cylindrical main axis; irregular ramifications are present with the alga reaching a height of $400\mathrm{mm}$. The receptacles are short and cylindrical, and whilst it has gas-filled vesicles, it is lacking in tophules. The main axis has a relatively soft texture, whilst the outer extremities are rough, almost spiny. It is a brown to olive green color and displays a bluish green iridescence when submerged [801].

3.4.40.2 Habitat

Grows in wave-exposed or moderately exposed places, in the upper sublittoral zone, always near the surface.

3.4.40.3 Distribution

Mediterranean.

3.4.40.4 Uses and Compounds

Extracts have antitumor [421, 62], antimicrobial [276, 284, 421, 96], andantifungal [276, 62] activity.

3.4.41 Cystoseira nodicaulis (Withering) M. Roberts

3.4.41.1 Common Name

Bushy noduled wrack.

3.4.41.2 Description

Thallus to $1\mathrm{m}$ long, usually solitary, attached by a irregular conical disk. Axis cylindrical usually branched, with smooth, rounded apex immersed between bases or tophules of developing laterals. Lateral branch systems (below) radial or distichous, with greenish-blue iridescence when first formed, about $50\mathrm{cm}$ long, repeatedly branched in a pinnate manner, either regularly or irregularly, with infrequent cryptostomata and bearing spine-like appendages; deciduous in summer; first-formed laterals of the season with tophules, later without; tophules ovoid, to $15\mathrm{mm}$ long, smooth or covered with small tubercles, persistent on axis after rest of lateral has been shed. Receptacles formed in the ultimate branchlets, simple or branched, nodose, usually bearing spine-like appendages; air vesicles inconspicuous, dilations of ultimate branchlets, solitary, in series or confluent; sometimes absent [802].

3.4.41.3 Habitat

Found in large intertidal rock pools and lagoons, often with C. tamariscifolia and C. baccata.

3.4.41.4 Distribution

Southern and western shores of Britain and Ireland, north to the Argyll in Scotland; Atlantic France and Spain, Portugal, Canary Islands, Morocco, south to Mauritania.

3.4.41.5 Uses and Compounds

Extracts have antileukemia activity [803].

3.4.42 Cystoseira spinosa Sauvageau

3.4.42.1 Description

Plant with a single axis, to $30$–$40\mathrm{cm}$ in height. Axis simple, to $20$–$30\mathrm{cm}$ hight: Apex of the axis not prominent and with spines; tophules spinose and oblong; branches both cylindrical and completely flattened, the latter with a pronouced midrib. Spinose appendages more abundantly present in the cylindrical than in the flattened branches; aerocysts absent [799].

3.4.42.2 Habitat

Occurs in the lower sublittoral zone.

3.4.42.3 Distribution

Mediterranean.

3.4.42.4 Uses and Compounds

Extracts have antifungal and antimicrobial activity [62, 804].

3.4.43 Cystoseira tamariscifolia (Hudson) Papenfuss

3.4.43.1 Common Name

Rainbow wrack

3.4.43.2 Description

C. tamariscifolia is a bushy seaweed, up to $60\mathrm{cm}$ in length but usually $30$–$45\mathrm{cm}$. It has a cylindrical frond and branches irregularly (Fig. 6.49). The reproductive bodies on the end of branches are long, oval and spiny. Small air bladders are usually found below the reproductive bodies. C. tamariscifolia is olive green in color, almost black when dry. When the plant is seen underwater it has a blue-green iridescence [805].

3.4.43.3 Habitat

Found in rock pools and on the lower shore; grows on both rocky shores and gravelly flats.

3.4.43.4 Distribution

NE Atlantic (United Kingdom to Mauritania); Mediterranean (France to Turkey).

3.4.43.5 Uses and Compounds

Extracts have antibacterial and antifungal [269, 438, 806, 807, 808], antioxidant and antitumor [731], and cytotoxic [317] activity.

3.4.44 Cystoseira usneoides (Linnaeus) M. Roberts

3.4.44.1 Description

Large sized thallus, formed by a central axis and lateral branches with secondary branches – the ones which are closer from basis are flattened and have a foliaceous aspect (Fig. 6.50); presents numerous vesicles [809].

Fig. 6.49

Underwater photo of C. tamariscifolia

Fig. 6.50

Cystoseira usneoides specimen

3.4.44.2 Habitat

Is present in relatively deep rocky areas crossed by currents.

3.4.44.3 Distribution

NE and E Atlantic (France, Spain, Portugal, Morocco, Senegal); Mediterranean (France, Spain, Algeria, Italy).

3.4.44.4 Uses and Compounds

Extracts have hypoglycemic and hypocholesterolemic [810], neuropharmacological [811, 812], anticancer, antioxidant, and anti-inflammatory [813] activity.

3.4.45 Cystoseira zosteroides C. Agardh

3.4.45.1 Description

Plant with a single axis, to $30\mathrm{cm}$ in height, attached to the substratum by simple or branched unfused haptera; axis branched or simple, to $10\mathrm{cm}$ high; apex of axis smooth and prominent; tophules cylindrical or ovoid, completely smooth, blackish or yellowish brown, sessile or with a sort peduncle; primary branches cylindrical or slightly flattened; secondary and tertiary branches foliaceous, several centimeters long and $1$–$1.5\mathrm{mm}$ wide, with an unpronounced midrib and with flattened and triangular spinose appendages, $1\mathrm{mm}$ long; aerocysts absent [799].

3.4.45.2 Habitat

Occurs in the lower sublittoral zone.

3.4.45.3 Distribution

Mediterranean.

3.4.45.4 Uses and Compounds

Extracts have antifungal and antimitotic activity [62].

3.4.46 Fucus ceranoides Linnaeus

3.4.46.1 Common Name

Horned wrack

3.4.46.2 Description

Large brown intertidal seaweed, restricted to growing in estuaries or near freshwater streams on the shore. F. ceranoides does not have airbladders, but the side of the fronds is often inflated. Frond thin with smooth margin, fan shaped with prominent midrib, without air bladders but frond on either side may be inflated, reproductive bodies’ narrow, pointed fronds at ends of branches [814].

3.4.46.3 Habitat

On estuaries or near freshwater streams on the shore, it attaches to stones, rocks, or gravel.

3.4.46.4 Distribution

F. ceranoides is widely distributed in NE Europe but is only common in brackish water. It is characteristic of estuaries and is often abundant where freshwater streams run onto the shore.

3.4.46.5 Uses and Compounds

Extracts have antioxidant and antitumor activity [205].

3.4.47 Fucus distichus Linnaeus

3.4.47.1 Common Name

Rock weeds

3.4.47.2 Description

A small tufted brown alga. It has narrow fronds without airbladders and short receptacles. The species has a life span of $3$ years and grows up to $30\mathrm{cm}$ long [815].

3.4.47.3 Habitat

Occurs in rock pools and on rock faces in the upper mid-littoral at wave exposed locations.

3.4.47.4 Distribution

NE Atlantic (Arctic to Britain and Ireland); NE Pacific (Alaska); Japan.

3.4.47.5 Uses and Compounds

Extracts have antimicrobial activity [816].

3.4.48 Fucus evanescens C. Agardh

3.4.48.1 Common Name

Arctic wrack

3.4.48.2 Description

Brown to olive green in color, broad blades, obvious midrib, with Y-shaped forks. Can grow up to $3$–$90\mathrm{cm}$ and can be difficult or to distinguish from F. vesiculosus, sometimes indistinguishable [817].

3.4.48.3 Habitat

Occurs in rock pools and on rock faces in the upper mid-littoral at wave exposed locations.

3.4.48.4 Distribution

NE Atlantic (Arctic to Britain and Ireland); NE Pacific (Alaska); Japan.

3.4.48.5 Uses and Compounds

Source of alginic acid, fucoidan, and used for animal feed [817, 818]. Extracts have antiviral [819, 820], antibacterial [821], antitrypanosomal [822], anti-inflammatory, antiangiogenic and antiadhesive [823], antithrombotic and hemorrhagic [824], anticoagulant [823, 825], antitumor [826, 827, 828], and immunostimulating [829, 830, 831] activity.

3.4.49 Fucus serratus Linnaeus

3.4.49.1 Common Names

Toothed wrack, Black wrack, Blackweed

3.4.49.2 Description

F. serratus is a robust, olive-brown shrubby seaweed. It can grow in high densities low on the shore, forming dense mats of long ribbons up to $1\mathrm{meter}$ long and $2$–$5\mathrm{cm}$ across. It attaches to rocks via a discoid holdfast about $3\mathrm{cm}$ in diameter. Though technically a brown alga, it can vary in color from olive green through reddish brown (though it often has a greenish tint). It typically grows up to $70\mathrm{cm}$ but has been recorded at over $2\mathrm{m}$ in length in very sheltered environments. The flat, strap-like fronds have a forward-pointing serrated edge, a distinct midrib, and grow from a short stipe. The fronds are bifurcating (splitting in two repeatedly) [832].

3.4.49.3 Habitat

On firm substrata in the lower mid-littoral; often zone forming.

3.4.49.4 Distribution

F. serratus is a seaweed of the North Atlantic Ocean. It extends from the Canary Islands and northern Portugal along the Atlantic coast of France, into the British Isles and North Sea coasts, and into the W Baltic. It is found in Scandinavia up to Novaya Zemlya, around Iceland, and over to the Gulf of St. Lawrence in the NW Atlantic, ranging from Chaleur Bay and the tip of Cape Breton to Bar Harbor, Maine.

3.4.49.5 Uses and Compounds

F. serratus survives by filtering the ocean for nutrients and as a result, amasses a huge amount of minerals and vitamins. Used for hundreds of years in seaweed baths, the oils from this seaweed have positive effects on skin, hair and body. The antioxidant [766] compounds found naturally in this seaweed have long been known to have pronounced antiaging, skin conditioning, and repair and hydrating effects. This seaweed is used as a food, and is harvested for cosmetics, and it is harvested to make fertilizer. Its edible properties are very similar to that of bladderwrack and interest in this plant is growing, as, being a thyroid stimulant it might could counter obesity by increasing the metabolic rate. It is also known to help women with abnormal menstrual cycling patterns and/or menstrual-related disease histories. It can be stored dried to make a nutritious tea as well as for use in soups and stews as a flavoring [833].

This species is collected, dried, and used as a soil additive as well. F. serratus is used by over a dozen businesses across the United States, Australia, France, Italy, Ireland, and the United Kingdom in a wide variety of products, such as: antiaging and eye serums, facial moisturizers and sunscreens, dental care compound, revitalizing compound used in skin and hair products, hair shampoos and conditioners, bath soak products, cleansing lotions, body buffs and gels, hand creams, facial, washes, cleansers, and toners, and fertilizers [833].

3.4.50 Fucus spiralis Linnaeus

3.4.50.1 Common Name

Spiral wrack

3.4.50.2 Description

Well-grown fronds are usually easily recognizable by the flattened, twisted, dichotomously branched thallus, lacking bladders, and the large, oval receptacles at the frond tips, each receptacle being surrounded by a narrow rim of vegetative frond. Nevertheless, younger plants are not always so easy to identify, and even mature plants can be confused with F. ceranoides or with bladderless forms of F. vesiculosus. Both of these species, however, have narrower, more pointed, rimless receptacles [834].

3.4.50.3 Habitat

Attaches to rocky substrata on sheltered to moderately exposed shores.

3.4.50.4 Distribution

F. spiralis is common on the coasts all around the British Isles, Iceland, W coasts of Europe, Canary Islands, Azores and Northeast North America from New Jersey to Nova Scotia. There are also isolated reports in the N Pacific.

3.4.50.5 Uses and Compounds

F. spiralis has been used historically for treatment of obesity, gout, goiter, and corns, and also in weight reducing and revitalizing bath treatments. It has been used for cattle feed, and as an organic manure. This alga, regularly exposed to sun radiation and its oxidative consequences, has developed optimal bioelectronics characters. It has a high concentration of phloroglucinol derivatives, including phenol acid, and in turn has been used in products from companies in France and the UK such as nutritional supplements, skin serum, body lotion, and compounds and extracts used as ingredients in other skin and hair products [835].

Extracts of this species have also antifouling [275], antimicrobial [269], antioxidant [225, 836, 837], anticoagulant [55], and antiproliferative [225] activity.

3.4.51 Fucus vesiculosus Linnaeus

3.4.51.1 Common name

Bladder wrack

3.4.51.2 Description

F. vesiculosus varies in color from olive green to olive brown to reddish brown to almost black and is typically about $40\mathrm{cm}$ in length (although fronds can grow longer). It attaches to rocky substrates by means of a small disk-shaped holdfast. F. vesiculosus is characterized by the small nearly spherical gas-filled vesicles (bladders) which look like bubblewrap and occur in pairs one on either side of an obvious central midrib running along the center of the strap-like frond (Fig. 6.51). The flattened, branching fronds can grow from one to two meters in length, and the air-filled bladders which keep the seaweed floating upright in its rocky anchorages increase its ability to photosynthesize. Typically it grows gregariously, forming dense mats of long ribbons up to one meter long and five centimeters across. The appearance of F. vesiculosus varies depending on the environmental conditions in which it occurs; in more sheltered areas there are many air bladders, whereas there are fewer in more exposed conditions. Also, in small plants, air bladders may be entirely absent. In exposed areas, it is beneficial for F. vesiculosus to lack bladders, as this decreases the potential for severe damage, and minimizes the risk of it being detached and swept away [1, 838].

Fig. 6.51

F. vesiculosus specimens

3.4.51.3 Habitat

On rocks and stones in the mid-littoral; often zone forming.

3.4.51.4 Distribution

F. vesiculosus is found on the coasts of the North Sea, the western Baltic Sea, and the Atlantic and Pacific Oceans. It occurs around the coastline of Greenland, Britain, Ireland, Norway, the Atlantic coast of France, Spain and Morocco, and the Atlantic coasts of Canada and the United States from Hudson Bay to North Carolina.

3.4.51.5 Uses and Compounds

Primary chemical constituents of F. vesiculosus include mucilage, alginic acid, mannitol, beta-carotene, zeaxanthin, iodine and iodine salts, bromine, potassium, volatile oils, and many other minerals, as well as polysaccharides. When used in hot seawater baths or steamed the plants are said to release certain substances that promote good skin, the lower blood pressure and ease arthritic and rheumatic pains. F. vesiculosus has been shown to help women with abnormal menstrual cycling patterns and menstrual-related disease histories. A popular use of F. vesiculosus in herbal medicine is as a source of iodine (it was the original source of iodine, discovered in 1811), an essential nutrient for the thyroid gland; it can be used in the treatment of underactive thyroid glands (hypothyroidism) and goiter, a swelling of the thyroid gland related to iodine deficiency [3, 4, 838].

Extracts of this species have genotoxic and antigenotoxic [839], antioxidant [717, 766, 840, 841], antithrombotic [842], antibacterial and antifouling [275], antiviral [843], antitumor [844, 845], and anticoagulant [512] activity.

3.4.52 Halidrys siliquosa (Linnaeus) Lyngbye

3.4.52.1 Common Name

Sea oak, Pod weed

3.4.52.2 Description

A large sturdy brown alga $0.3$–$1\mathrm{m}$ in length (occasionally up to $2\mathrm{m}$) rising from a strong, flattened cone shaped holdfast. The main stem is flattened and branches alternately to give a distinctly zigzag appearance. The stem bears a few, flattened ribbon-like leafy fronds. The ends of some branches bear characteristic pod-shaped air bladders (about $0.5\mathrm{cm}$ wide by $1$–$4\mathrm{cm}$ long) that are divided by transverse septa into $10$ or $12$ compartments. The branches also bear reproductive bodies that appear similar to the bladders but lack the septa. Young plants are olive-green in color while older specimens are dark brown and leathery. This species is perennial [846].

3.4.52.3 Habitat

Distinctive and common rock pool seaweed from the middle to the lower shore (may be found in the upper mid-littoral but only in rock pools). It may also form a zone in the sublittoral below the lower limit.

3.4.52.4 Distribution

NE Atlantic (from Faroe Islands to Portugal, North Sea, Baltic).

3.4.52.5 Uses and Compounds

Source of alginic acid. Extracts have antibiotic [847, 848], antifouling [849], antioxidant, and antitumor [421, 731] activity.

3.4.53 Himanthalia elongata (Linnaeus) S.F. Gray

3.4.53.1 Common Names

Sea spaghetti, Sea thong

3.4.53.2 Description

Common brown seaweed, which has a two stage morphology. Small button-like thalli are first produced, from which long strap-like reproductive fronds (receptacles) are formed in autumn (Fig. 6.52). The strap-like reproductive fronds grow quickly between February and May, reaching a length of up to $3\mathrm{m}$. The plant releases gametes from June until the winter when it starts to decay. Plants commonly live for $2$–$3$ years and reproduce once before dying [1].

Fig. 6.52

Himanthalia elongata specimen

3.4.53.3 Habitat

H. elongata is common on gently shelving rocky shores attached to hard substrata such as bedrock, or large to very large boulders. It is found on the lower shore flourishing at the low tide limit with moderate wave exposure where its thallus is typically always submerged, and is considered a sublittoral species.

3.4.53.4 Distribution

H. elongata can be found from the Arctic Ocean south to the Iberian Peninsula, in the waters of the Baltic Sea, the North Sea and the northeast Atlantic Ocean. It is seen on the shores of Norway, the Faroes, Britain, Ireland, the western coast of France, northern Spain, and Portugal.

3.4.53.5 Uses and Compounds

H. elongata is known to provide high levels of Vitamins A, C, and E along with essential amino acids and other natural minerals. It has several properties which make it attractive as an ingredient in personal care and cosmetic products, such as that it is absorbent, viscosity controlling, skin protecting, and can be used as a binding agent. It has a natural ability to help restore balance to skin’s moisture levels. It is used in dozens of products made in Ireland, France, Spain, Italy, Canada, and the United States [3, 4, 850].

H. elongata is used in shampoos and hair treatments, facial cleansers and skin care products, and also as a fertilizer. It can be sold and eaten fresh when in season, but it is typically sold dried or pickled, and is eaten most commonly in France and Ireland. It is used as an alternative to both traditional semolina spaghetti and green beans. It is found in popular tartar (sauce), tahini, pâté and cream products, and also in sea vegetable mixes [3, 4, 850].

Extracts of this species have hypoglycemic [851], antibiotic [852, 853], neuropharmacological [854, 855], antimicrobial, and antioxidant [429, 533, 765, 766, 856, 857] activity.

3.4.54 Pelvetia canaliculata (Linnaeus) Decaisne & Thuret

3.4.54.1 Description

P. canaliculata, often called channeled wrack, is a very common brown alga (Phaeophyceae) of Europe. It is the only species remaining in the monotypic genus Pelvetia. It is relatively small, not growing longer than $15\mathrm{cm}$. When viewed underwater, its color can be light olive green, and sometimes yellowish brown (Fig. 6.53). P. canaliculata’s color can range from dark brown to dark olive to very dark or blackish green when dried. Its extremities can appear swollen and with orange during spring and summer. These bumpy, irregularly v-shaped swellings with forked tips at the ends of the fronds are its reproductive structures. It appears bushy and grows in dense tufts. Each frond is curled longitudinally (rolled lengthwise) to form a distinct channel. It is irregularly dichotomously branched; each tough and thick branch is of uniform width up to $1\mathrm{cm}$, lacks a midrib, and lacks air vesicles or bladders. P. canaliculata is a  perennial species; it is at least two years old before it reaches maturity, and has a life span of up to $4$ or $5$ years, growing $3$ – $4\mathrm{cm}$ per year [1, 858].

Fig. 6.53

Pelvetia canaliculata specimens

3.4.54.2 Habitat

P. canaliculata grows attached to hard substrata with a small basal disk on the upper shore, and forms the uppermost zone of algae growing at or above high water mark. It needs periods of exposure to the air, and sometimes grows so high up a beach that coarse grass and other long-shore angiosperms grow among it. P. canaliculata is found right at the top of the beach in sheltered to moderately exposed areas where it can dry out completely to become black and crispy.

3.4.54.3 Distribution

One can find P. canaliculata in the northeast Atlantic, from the Arctic Ocean to the Iberian Peninsula, in the English Channel, and in the North Sea. It is common on the Atlantic shores of Europe from Iceland to Spain, including Norway, Ireland, the UK, the Netherlands, France, and Portugal (southern limit of this species).

3.4.54.4 Uses and Compounds

P. canaliculata was historically harvested for use as animal fodder, and in certain areas there are still animals which graze on the growing plants. It has also been collected historically as a source of food for people. It is included in dozens of products from Italy, France, United Kingdom, and the United States. According to one leading cosmetics producer, P. canaliculata stimulates the synthesis of collagens and proteoglycans, which are responsible for giving connective tissue its elastic properties. Using it as a compound can increase the skin’s firmness and reduce the appearance of lines and wrinkles. It is reported from another leading cosmetics company that it increases microcirculation and can help reduce fat and cellulite. P. canaliculata can be found on ingredient labels for moisturizing lotions, masks and creams, and in body creams, day creams, and night creams. It is found in quality restorative and hydrating serums, and in compounds and extracts used in different products. For food, it is sold in different dried forms, and as a seasoning mix [858].

Source of alginic acid and fucoidan [859], and the extracts of this species have antioxidant [860, 861], anticoagulant [862], antifungal [863], antifouling [275], and antibiotic [864] activity.

3.4.55 Sargassum filipendula C. Agardh

3.4.55.1 Description

The habit of S. filipendula is so like that of other species which have been described that it needs but slight attention. This species grows attached to rocks below low water mark, and therefore, unlike Fucus and Ascophyllum, is never exposed to the air. Vegetative plants and reproductive plants bearing all stages of conceptacles are plentiful in summer. Sporelings are abundant also and easily collected, for the discharged eggs and their products, the sporelings, remain attached for some time by mucilage to the surface of reproductive branches near the parent conceptacles. The stem arises from a small disk-shaped holdfast and passes into long cylindrical branches which bear spirally arranged leaves, berry-like floats, which seem to be modified portions of leaves, as generally stated, and short reproductive branches. This form may attain a height of $60\mathrm{cm}$, but is commonly shorter [865].

3.4.55.2 Habitat

On firm substrata in the shallow sublittoral, to $6$ $(-30)\mathrm{m}$ depth.

3.4.55.3 Distribution

NE Atlantic (Spain and Portugal to Gabon), Caribbean (Cuba), SW Atlantic (Mexico to Brazil).

3.4.55.4 Uses and Compounds

Extracts have antitumor [866, 867, 868, 869], antioxidant [679, 866, 868, 869], and antifungal [863, 870] activity.

3.4.56 Sargassum hornschuchii C. Agardh

3.4.56.1 Description

Differs from the S.vulgare for the shape of the leaves: laminated in S. vulgare and triangular section in S. hornschuchii [871].

3.4.56.2 Habitat

On firm substrata in the shallow sublittoral, to $6$ $(-30)\mathrm{m}$ depth.

3.4.56.3 Distribution

Mediterranean.

3.4.56.4 Uses and Compounds

Extracts have antifungal [62], cytotoxic, and antitumor [197] activity.

3.4.57 S. muticum (Yendo) Fensholt

3.4.57.1 Common Names

Japanese seaweed, Japanese brown alga, Japweed, Wire weed, Strangle weed.

3.4.57.2 Description

S. muticum is a large brown seaweed, varying in color from dark brown to pale, yellowish brown depending on the season and the growing conditions. S. muticum has regularly alternating lateral shoots or branches, on a central perennial stem (Fig. 6.54). It attaches to the substrate with a  disk-shaped holdfast. It has numerous small $2$–$3\mathrm{mm}$ round or pear-shaped air-bladders which sit on small stems and cause the alga to stand upright in the water or float if parts of the alga are detached from the basal stem. S. muticum has a frond which may be $75$–$120\mathrm{cm}$ long in its native range, but normally reaches a length of $1.5$–$2\mathrm{m}$ in Swedish waters, $6$–$7\mathrm{m}$ in French waters, and up to $8.5\mathrm{m}$ in Norwegian waters. Lateral branches detach in the summer or autumn, leaving a short perennial basal stem to overwinter [872]. During the summer, cigar-shaped reproductive receptacles develop in the areas where the annual shoot or branch attaches to the stem, but may also sit on top of the branch [1, 873].

Fig. 6.54

Underwater photo of S. muticum

3.4.57.3 Habitat

In the mid-littoral and to below the tidal mark ($3$–$5\mathrm{m}$).

3.4.57.4 Distribution

Highly invasive: originally from Japan, it now colonizes large parts of the NE Atlantic (Norway to Portugal, North Sea), the W Mediterranean, and the N Pacific: NW Pacific (Japan), NE Pacific (Alaska to Mexico).

3.4.57.5 Uses and Compounds

Source of Laminaran [873], and extracts have antitumor and antibacterial [113], antioxidant [874], antialgal [257], antifungal [863], antibiotic [875], and antifouling [876, 877, 878, 879, 880] activity.

3.4.58 Sargassum natans (Linnaeus) Gaillon

3.4.58.1 Description

S. natans, unlike the many benthic Sargassum species (i. e., those that live attached to the sea bottom), is a pelagic (free-floating) brown seaweed that occurs mainly far out in the North Central Atlantic Ocean, but washes ashore regularly. It is often associated with the Sargasso Sea, a very large region situated offshore from the southeastern United States, approximately south and east of Bermuda and seaward from the Gulf Stream. The Sargasso Sea, which accumulates large masses of Sargassum, results from a ring of prevailing ocean currents that enclose an enormous eddy (about $5.2\mathrm{million}{\mathrm{km}}^2$) which rotates clockwise as a result of the Earth’s eastward rotation. S. natans apparently reproduces only asexually, by fragmentation. Gower and King [881, 882] used satellite imagery to track the origin, distribution, and fate of floating Sargassum. Using this approach, they analyzed data from 2002 to 2008 and were able to present the first mapping of the full distribution and movement of pelagic Sargassum in the Gulf of Mexico and western Atlantic. Their results revealed a seasonal pattern in which Sargassum typically shows strong growth in the northwest Gulf of Mexico in the spring of each year, is transported into the Atlantic in about July, appearing east of Cape Hatteras as a Sargassum jet, and ends up northeast of the Bahamas in February of the following year.

3.4.58.2 Habitat

On firm substrata in the shallow sublittoral, to $6$ $(-30)\mathrm{m}$ depth.

3.4.58.3 Distribution

NE Atlantic (Spain); Atlantic Islands; NW Atlantic; Caribbean; SW Atlantic; Pacific Ocean (Indonesia); Australia.

3.4.58.4 Uses and Compounds

Source of alginic acid [883] and extracts of this species have antimicrobial [136, 884, 885], antifouling [275], and antitrypanosomal [822] activity.

3.4.59 Sargassum vulgare C. Agardh

3.4.59.1 Description

S. vulgare has a bush-like thalli reaching $15$–$70\mathrm{cm}$ high; the fronds are oval, flattened, olive-green to brown and possess a central rib and undulated edge. The base of the fronds has hollow, spherical vesicles, of $5$–$8\mathrm{mm}$, and clusters of reproductive bodies; these are held in place by a pedicle. The alga is attached to the substrate with irregular rhizoidal branches. S. vulgare has an olive brown to dark brown coloration [886].

3.4.59.2 Habitat

On firm substrata in the shallow sublittoral, to $6$ $(-30)\mathrm{m}$ depth.

3.4.59.3 Distribution

NE Atlantic (Portugal, S Spain to Canary Islands); Mediterranean; Caribbean; SE Atlantic (W Africa); W Pacific (Philippines); Indian Ocean.

3.4.59.4 Uses and Compounds

Source of alginic acid [765, 886, 887] and extracts of this species have antihelminthic [886], antioxidant, antimicrobial and antifungal [336, 888, 889], antitumor [765, 890, 891], antilipemic [892], antifouling [893, 894], antimicrobial [228], anticoagulant, antithrombotic, and anti-inflammatory [889] activity.

• Order: Laminariales

3.4.60 Alaria esculenta (Linnaeus) Greville

3.4.60.1 Common Name

Dabberlocks.

3.4.60.2 Description

Fronds with olive or yellow-brown fronds to $4\mathrm{m}$ long and $25\mathrm{cm}$ wide. Attached by a root-like holdfast at the base from which a narrow flexible stipe arises which continues into the leafy part of the plant as a distinct mid-rib (Fig. 6.55). The reproductive structures, apparent as dark-brown areas, are confined to unbranched leafy appendages borne on the stipe, usually in two rows. This is the only kelp-like plant in Ireland and Britain with a distinct midrib and is the only one with sporangia borne at the base of the frond in special leaflets called sporophylls [895, 896].

Fig. 6.55

Herbarium specimen of Alaria esculenta (MACOI no. 2664)

3.4.60.3 Habitat

Generally grows on rock in very exposed places, often forming a band at low water and in the shallow sublittoral, but also occurs in tidal pools in the lower shore.

3.4.60.4 Distribution

Coasts of the North Atlantic (France, Scotland, Ireland, Greenland, Iceland, northeastern United States, northeastern Canada), the N Sea (England, Norway, Netherlands), Novaya Zemlya to the N Pacific (Bering Sea and Sea of Japan).

3.4.60.5 Uses and Compounds

A. esculenta can be used for a variety of purposes from human consumption and alginate production to fodder and body-care products. It is rapidly gaining popularity in the natural foods market. It can be ordered from many sellers as whole, flaked, milled, or powdered. It is used for antiaging body creams, foot creams, bath soaks, body and face masks, body polish, GlossaryTerm

UV

-protecting facial moisturizers, self-tanning lotions, lip balm, day- and night-creams, and nutritional supplements to name a few. In Canada and the United States, this seaweed is sometimes sold as Atlantic Wakame and is presented as an alternative to traditional Japanese Wakame (Undaria pinnatifida). A. esculenta also has potential as a foodstuff in aquaculture for herbivorous molluscs such as abalone. Over $20$ sellers with over $70$ A. esculenta-based products have been identified. These sellers are from Germany, Italy, France, Ireland, United Kingdom, Canada, and the United States [4, 896, 897].

3.4.61 Chorda filum (Linnaeus) Stackhouse

3.4.61.1 Common Names

Sea lace; dead man’s rope; mermaid’s tresses; Cat gut.

3.4.61.2 Description

C. filum is a brown seaweed with long cord-like fronds, only $5\mathrm{mm}$ thick in diameter. The fronds are hollow, slippery, unbranched, and grow up to $8\mathrm{m}$ long. The species is attached to the substratum using a small discoid holdfast. It is an annual species, disappearing in winter [898, 899].

3.4.61.3 Habitat

It is found in rock pools on the low shore and in the sublittoral down to $5\mathrm{m}$. It is most commonly found in the sheltered bay.

3.4.61.4 Distribution

Abundant throughout the North Atlantic, on the shores of Europe and America, coast of Brazil, and also in the North Pacific, at Sitka, Unalaschka, and Kamtschatka.

3.4.61.5 Uses and Compounds

C. filum is used fresh as a foodstuff, and for animal feed [898]. This species produces alginate and fucoidan, and have antimicrobial [474, 546, 844, 898, 900], algicidal [257], anticoagulant [524], and antioxidant [474] activity.

3.4.62 Laminaria digitata (Hudson) J.V. Lamouroux

3.4.62.1 Description

A large conspicuous kelp growing up to $2\mathrm{m}$ in length commonly found at low water during spring tides on rocky shores. The frond is broad and digitate, glossy and dark brown in color and lacks a midrib. The stipe is oval in cross section, smooth and flexible and is usually free of epiphytes, although old stipes which has become slightly roughened may support a few epiphytes, notably Palmaria palmata. The kelp is attached to freely branched haptera, which spread out to form a shallow dome-shaped holdfast. L. digitata may be confused with young L. hyperborea plants. However, the stipe of L. hyperborea is circular in cross section, is stiff, and snaps easily when bent (although you would not see that in younger fronds) [901, 902].

3.4.62.2 Habitat

On rocks from the low water spring tide level to the shallow sublittoral. In some locations, L. digitata may be found in deeper water.

3.4.62.3 Distribution

L. digitata is a North Atlantic Arctic-cold-temperate species which does not occur in the North Pacific. It is found along both coasts of the English Channel; the southernmost occurrence of this species in European waters is on the southern coasts of Brittany. It grows along most coasts of Britain and Ireland, and along the North Sea coasts of Scandinavia. Its northerly range includes into the Barents Sea and the western shores of Novaya Zemlya, and has been reported to occur in the Svarlbard Archipelago. L. digitata also grows in Iceland, the Faeroes, southern Greenland, and the eastern coasts of North America, as far south as Cape Cod.

3.4.62.4 Uses and Compounds

L. digitata plants contain minerals, vitamins, and trace elements. These include iodine, calcium, potassium, iron, carotene, alginic acid, laminaran, fucoidan, mannitol, protein, carotene, niacin, phosphorus, the B complex vitamins, vitamin C, and many other trace elements. This species stores flavor-enhancing glutamic acid, or sodium glutamate, which imparts a mellow, silky taste to dishes. The slight sweet background is mannitol, a natural sugar. In terms of relatives, L. digitata is closely related to the five species (Saccharina latissima, S. japonica, L. angustata, L. longissima, and L. ochotensis) typically harvested as Kombu in Japan, and is frequently harvested and sold as Kombu in North America. Many recipes calling for Kombu could be made with this form of kelp [901, 902, 903, 904, 905, 906].

Extracts of this species have antibacterial [371], and antioxidant [766] activity.

3.4.63 L. hyperborea (Gunnerus) Foslie

3.4.63.1 Common Name

Oarweed.

3.4.63.2 Description

L. hyperborea is often difficult to distinguish from L. digitata, particularly when plants are young (Fig. 6.56). However, the stipe of L. digitata is darker and usually oval in cross section instead of cylindrical, is not thicker at the base, does not snap easily, and does not have epiphytes on the stipe. Also, the belt of L. hyperborea is nearly always below (in deeper water) any belt of L. digitata. L. ochroleuca is a similar species, but has a smooth stipe (not rough like L. hyperborea), and its fronds are typically more golden or yellow. Saccorhiza polyschides, another commercially utilized kelp, appears similar to L. hyperborea from the frond, but has a twisted stipe near a bulbous haptera, which is very different from L. hyperborea’s bird claw holdfast [1, 907].

Fig. 6.56

Saccorhiza polyschides (left) and L. hyperborea (right)

3.4.63.3 Habitat

Found on bedrock or other stable substrata from extreme low water to depths dependent on light penetration and sea urchin grazing (typically about $8\mathrm{m}$ depth in coastal waters to $30\mathrm{m}$ in clear coastal).

3.4.63.4 Distribution

L. hyperborea is a European North Atlantic cold-temperate species which does not extend into areas influenced by Arctic waters; its range is the NE Atlantic Ocean, from Scandinavia south to Spain and the Canary Islands, the Baltic Sea, and the North Sea.

3.4.63.5 Uses and Compounds

In Europe, L. hyperborea is one of the two kelp species commercially exploited by the hydrocolloid industry, the other being L. digitata. L. hyperborea is also utilized by the cosmetic and agrochemical industries and for biotechnological applications, and by the food industry for emulsifiers and gelling agents. Drift kelp has long been collected as an agricultural fertilizer and soil conditioner. L. hyperborea is still harvested and used in popular kelp meal fertilizer products. L. hyperborea is a source of laminarin and mannitol, which are used in industrial and other applications. Because of its ability to absorb and retain water, it has been used in wound dressings to prevent adhesions, and has also been used to help dilate the cervix during childbirth [3, 907].

Extracts have antifungal [863], anticoalgulant [512], antibacterial [765], antioxidant [860], and anticoagulant [524] activity.

3.4.64 Laminaria ochroleuca Bachelot de la Pylaie

3.4.64.1 Common Names

Kelp, Kombu.

3.4.64.2 Description

L. ochroleuca is a glossy, yellow-brown kelp that is prevalent along the intertidal zones. This kelp is quite conspicuous as it grows quite large under the right conditions. The maximum length recorded is $4\mathrm{m}$ long, but this length is rarely attained and occurs only in specific areas. Under normal conditions L. ochroleuca is more likely to reach a maximum length of about $2\mathrm{m}$. It has a large heavy holdfast made up of thick haptera (up to $18\mathrm{cm}$ in diameter) that support the plant and anchor it to rock. This holdfast gives rise to a fairly long, rigid, round, epiphyte-free stipe that tapers somewhat as it approaches the blade. This stipe is so strong and stiff that it stands erect when the plant is out of the water. The blade of this kelp is large, flat, and leathery, and is divided into 5–20 strap-like digits. This kelp is easily distinguished by the distinct yellow area at the junction of the stipe and the blade. The entire plant actually has a very lovely yellowish hue to its smooth, bright, glossy tissue. L. ochroleuca is a perennial kelp that retains its stipe and holdfast year long but regenerates a new blade each year [1, 908].

3.4.64.3 Habitat

This species is found on rocks from the low water spring tide level to the shallow sublittoral. In some locations L. ochroleuca may be found in deeper water.

3.4.64.4 Distribution

L. ochroleuca is a warm-temperate species of kelp, and is most common in the NE Atlantic from the British Isles to the Sahara and the Atlantic zones of the Mediterranean.

3.4.64.5 Uses and Compounds

Extracts of L. ochroleuca have been found to act as a central nervous system depressant with a slight analgesic activity. It is also able to effectively guard GlossaryTerm

DNA

against GlossaryTerm

UV

rays and premature aging. With these properties, it is becoming more widely used in cosmetics and in natural therapeutic medicine. Applied topically, L. ochroleuca helps reduce inflammation and, like many forms of seaweed, has some amount of moisture-binding properties due to its sterol content. It is used in products from Spain, Germany, France, and the United Kingdom; these include rescue balms, repairing and antiaging moisturizers, as well as dried and packaged foods [3, 4, 908, 909].

Extracts have also antimicrobial [224, 269, 910, 911, 912, 913], antifungal [913], and antialgal [257] activity.

3.4.65 Saccharina latissima (Linnaeus) C.E. Lane, C. Mayes, Druehl & G.W. Saunders

3.4.65.1 Synonym

Laminaria saccharina (Linnaeus) J.V. Lamouroux

3.4.65.2 Common Names

Sugar kelp, Sea belt, Sugar wrack.

3.4.65.3 Description

Just like most kelps, S. latissima has blades (lamina), stipes, and holdfasts, which is attached to substrates. The sporophytes of S. latissima have a rich medium brown color, a long undivided frond without a midrib and a profusely branched holdfast (Fig. 6.57). Mucilage ducts are absent from stipe; the blade often has two rows of bullations formed in two longitudinal rows parallel to the central axis. The frond of S. latissima has a distinctive frilly undulating margin. The stipe of S. latissima may be up to $50\mathrm{cm}$ long [1, 914].

Fig. 6.57

Saccharina latissima specimen

3.4.65.4 Habitat

S. latissima is usually found from the sublittoral fringe down to a depth of $30\mathrm{m}$. More rarely, it occurs in rock pools. The species usually occurs in sheltered conditions and may be attached to unstable substrata such as boulders and cobbles.

3.4.65.5 Distribution

N and NE Atlantic (Greenland to Portugal, North Sea, Baltic); NW Atlantic (Canadian Arctic to Massachusetts); NE Pacific (Alaska to California).

3.4.65.6 Uses and Compounds

Kelp harvesting is also an important industry around the world. Kelp products, alginic acid and fucoidan, are used for different purposes [915]. Alginic acid is a common polysaccharide constituent of kelp cell walls and it can be used to form gels. Alginic acid is used as a stabilizer in the food, cosmetic, and pharmaceutical industries: yogurts, shampoos, skin creams, lotions as well as ice creams. Alginic acid is also being used in many dietary products because human body cannot absorb it. In lots of biotechnological research experiments, alginic acid is used to separate substances [3, 4].

People eat Sugar kelp (also called Kombu in Japanese dishes), which contains appreciable amount of vitamin C and is high in iodine, protein, and calcium. The blade is usually chopped and cooked as a savory garnish (Tororo Konbu) for rice and other dishes, as a vegetable, and as snacks (such as Tsukudani). Kombu is also used to add flavor to broths (Dashi stock) and stews but it removes itself removed from the liquid at the end of cooking and discarded. It can be used to soften beans during cooking, and to help convert indigestible sugars [4].

Extracts of this species have anticoagulant [512, 524], antifouling [916], antimicrobial [533, 816, 917], and antioxidant [429, 533, 860] activity.

3.4.66 Saccharina longicruris (Bachelot de la Pylaie) Kuntze

3.4.66.1 Description

S. longicruris is a particularly tall species of kelp. The hollow, cylindrical stipe itself can reach up to $10\mathrm{m}$ long, plus the frond which adds another 1–2 m. The large branched holdfast grips firmly to the rocky substrate allowing a single long, thin, olive-brown, leafy blade to float near the surface. The midsection of these blades is somewhat thicker, but the edges spread and thin and become wide and ruffled. S. longicruris is limited to the sublittoral zone, but can be found either in shallow or in much deeper waters, often preferring areas with a strong flow. In this environment, it is a dominant part of the seaweed community and forms dense multistory forests with older plants forming a canopy of fronds floating on the surface and younger plants protected underneath [918].

3.4.66.2 Habitat

Horizontal distribution is determined to a large extent by substratum type and salinity. In very sheltered sites the species can occur on an unstable substratum of gravel and small stones.

3.4.66.3 Distribution

The species occurs widely throughout the NW Atlantic and eastern Arctic Oceans, mostly within Canadian territorial waters, and along the west coast of Greenland north of ${62}^{\circ }$ N. The species is rare on the east coast of Greenland, but has been recorded from Iceland, the Faeroes and as far south as Long Sound on the Shetland Islands at the latitude of ${60}^{\circ }$ N. S. longicruris has not been recorded from the European mainland.

3.4.66.4 Uses and Compounds

S. longicruris is an edible species of kelp that is related to traditional Japanese Kombu, but is thinner, tenderer, and cooked fastly. It is high in minerals and micronutrients and is particularly delicious as it contains naturally occurring monosodium glutamate – a little known feature of many kelp species [918, 919].

Extracts have immunostimulatory [920], and skin antiaging [921] activity.

3.4.67 Saccorhiza polyschides (Lightfoot) Batters

3.4.67.1 Common Name

Furbelows.

3.4.67.2 Description

S. polyschides is kelp species with a distinctive large warty holdfast and a flattened stipe with a frilly margin (Fig. 6.56). The stipe is twisted at the base and widens to form a large flat lamina, which is divided into ribbon-like sections. The species is an annual, and very fast growing. It is opportunistic and colonizes available hard substrata in the sublittoral [1, 922].

3.4.67.3 Habitat

In the lower littoral, in calm shallow water to $19\mathrm{m}$.

3.4.67.4 Distribution

NE Atlantic (Norway to Morocco), W Mediterranean.

3.4.67.5 Uses and Compounds

Source of alginic acid, and possible source of biofuel [380]. Extracts of this species have hypoglycemic [923], antisettlement [360], cytotoxic, and antiplasmodial [924] activity.

3.4.68 U. pinnatifida (Harvey) Suringar

3.4.68.1 Common Name

Wakame.

3.4.68.2 Description

U. pinnatifida belongs to the order Laminariales, with three clearly recognizable parts comprising its visible thallus: blade, stipe, and holdfast. The thallus can reach 1–3 m in length. The blade is lanceolate and broad with a prominent midrib, and translucent with color ranging from green to yellowish brown to dark brown. The blade could also be described as triangular and lobed (Fig. 6.58). The appearance of the blade evolves and changes over time; it is initially simple, flattened, and broad with a pronounced or distinct midrib; older plants have thicker blade tissue which splits horizontally down to the midrib to form fingers or straps, becoming more transversally lobed, and becomes pinnate with age. The margins of the blade can also be described as wavy. The distal portion of the blade and the straps eventually become tattered. The stipe of U. pinnatifida is wavy or corrugated above the holdfast. The stipe is also usually short (10–30 cm) in length and up to $1\mathrm{cm}$ in diameter) and in mature plants bears convoluted wing-like reproductive outgrowths or frills (sporophylls). The stipe is also flattened, and transitions into the midrib which extends through the middle of the length of the blade. U. pinnatifida is attached to its substrate by a branched holdfast comprised of haptera. It may be confused with A. esculenta, as it also has a prominent midrib, but the corrugated stipe of U. pinnatifida (which contains its sporophylls) is distinctive. Also, A. esculenta grows in more exposed and wave-battered locations than U. pinnatifida [1, 4, 925].

Fig. 6.58

U. pinnatifida specimen

3.4.68.3 Habitat

Wakame is economically important as a food crop but is also a fouling organism. It is able to compete with native Kelp species in the shallow sublittoral zone.

3.4.68.4 Distribution

Worldwide distribution.

3.4.68.5 Uses and Compounds

U. pinnatifida is economically important as a food crop, next to Nori, on the Japanese menu, and is eaten both dried and fresh. In East Asian countries the seaweed is known as Wakame and is treated as a delicacy, often added to miso soup. It can be considered a sea vegetable, or edible seaweed. Wakame fronds are green and have a subtly sweet flavor and slippery texture. In Asia and Europe, Wakame is distributed either dried or salted, and used in soups (particularly miso soup), and salads (such as tofu salad), or often as a side dish to tofu and a salad vegetable like cucumber. Goma wakame, also known as seaweed salad, is a popular side dish at some sushi restaurants; literally translated, it means sesame seaweed. In Korea, U. pinnatifida is used in salads or soup such as Miyeokguk. Many women consume U. pinnatifida during pregnancy, and Miyeokguk is popularly consumed by women after giving birth as Miyeok contains a high content of calcium and iodine, nutrients that are important for nursing new mothers. It is also traditionally eaten on birthdays for this reason, a reminder of the first food that the mother has eaten and passed on to her newborn through her milk, thus bringing good fortune for the rest of the year. After the species was accidentally introduced in 1971 in the Mediterranean via farming of Japanese oysters (Crassostrea gigas), U. pinnatifida was grown in the French Bretagne as food, which increased exposure of this seaweed to Europeans. U. pinnatifida is also used in a wide variety of topical beauty treatments and personal care products, due to its high polysaccharide content and ability to provide moisture [3, 4, 925].

Extracts of this species have antihypertensive [926], immunomodulating [927], antidiabetic [928], antiviral [929, 930], cytotoxic [931], antioxidant [932], antitumor [933, 934], antiedema [935], antiplasmodial [936], anti-osteoporotic [937], anti-inflammatory [938], antiobesity [939, 940], antihypertensive [941], and antithrombotic [942] activity.

• Order: Ralfsiales

3.4.69 Ralfsia verrucosa (J.E. Areschoug) J.E. Areschoug

3.4.69.1 Description

R. verrucosa is an olive brown to khaki encrusting brown seaweed that occurs abundantly in low shore tide pools. Here it often forms large, flat, smooth expanses giving the impression that someone had accidentally dropped khaki paint into the tide pools. R. verrucosa can occur in high abundance because of its relatively fast growth rate and also because it produces a chemical which seems to deter most grazers [943].

3.4.69.2 Habitat

Saxicolous, mid-littoral.

3.4.69.3 Distribution

NE Atlantic (Ireland and Britain to Morocco); SE Atlantic (South Africa); NW Atlantic (Canada, USA); SW Atlantic (Argentina); Mediterranean; Indo-Pacific; Australia.

3.4.69.4 Uses and Compounds

Extracts have antibacterial and antifouling activity [944].

• Order: Sphacelariales

3.4.70 Cladostephus spongiosus (Hudson) C. Agardh

3.4.70.1 Description

Fairly stiffly branched fronds growing from a crust-like discoid holdfast, covered with small branchlets arranged in whorls (Fig. 6.59); maximum length is usually about $15\mathrm{cm}$ [945].

Fig. 6.59

Herbarium specimen of Cladostephus spongiosus (MACOI no. 3509)

3.4.70.2 Habitat

On firm substrata in the intertidal zone.

3.4.70.3 Distribution

NE Atlantic (Iceland to Morocco); Mediterranean, Indian Ocean; Australasia; Antarctica, Sub-Antarctic Islands.

3.4.70.4 Uses and Compounds

Extracts have antibacterial activity [171, 201].

3.4.71 Halopteris filicina (Grateloup) Kützing

3.4.71.1 Description

Compressed, tufted, dark purplish brown fronds, to $120\mathrm{mm}$ high, main axis $1$–$4\mathrm{mm}$ broad. Once or twice pinnate, axes and branchlets tapered at base and apex [946].

3.4.71.2 Habitat

On rocks in pools, mid-littoral to shallow sublittoral, sporadic, often locally common.

3.4.71.3 Distribution

NE Atlantic (Ireland and Britain to Morocco); Mediterranean; NW Atlantic (USA); SW Atlantic (Brazil); NE Pacific (South Korea, Japan).

3.4.71.4 Uses and Compounds

Extracts have antihelminthic [946], antimicrobial [130, 201, 203, 40], antifouling [947], antifungal and antimitotic [62] activity.

3.4.72 Stypocaulon scoparium (Linnaeus) Kützing

3.4.72.1 Synonym

Halopteris scoparia (Linnaeus) Sauvageau.

3.4.72.2 Common Name

Sea broom.

3.4.72.3 Description

S. scoparium, previously known as H. scoparia, is a dark brown algae that forms beautiful fluffy clumps in shallow rocky-bottomed water. Growing only up to $15\mathrm{cm}$ in length, S. scoparium has a main axis with alternate plumed branches which are more or less fan shaped when flat, though when buoyed up by water they form inverted cone-shaped tufts with a very delicate appearance due to the many filamentous branches. Plants are usually attached to rocks with small to extensive disks often obscured by many matted rhizoids; though these are lacking in free-living plants. These plants are characterized by pure, sheltered waters with high light levels. S. scoparium often forms clumps on cobble in the shallow sublittoral zone, though they are just as likely to be found in shallow tide pools or sandy-bottomed areas [32, 948].

3.4.72.4 Habitat

On rocks and epiphytically on other seaweeds; in sheltered zones of the upper littoral and in up to $5\mathrm{m}$ depth.

3.4.72.5 Distribution

NE and E Atlantic (Scandinavia to Cap Verde Islands); Mediterranean.

3.4.72.6 Uses and Compounds

S. scoparium is known to be an ingredient in compounds used in personal care products; it contains growth substances (phytohormones) that include auxins, gibberellins, cytokinins, abscissic acid, and betaines [948].

Extracts of this species have antiprotozoal [193], antifungal and antimitotic [62], antioxidant [949], antileukemia [950], and antimicrobial [296] activity.