New and noteworthy species of Inocybe (Agaricales) from tropical India

Abstract

Eleven species of Inocybe, a highly diverse genus of ectomycorrhizal Agaricales, are documented from tropical India in Kerala State. Seven species are described as new. Furthermore, I. pileosulcata is reported from India for the first time. I. virosa, not previously validated, is validated here. Gross morphological and microscopic descriptions, illustrations, and phylogenetic affiliations are provided. Seven species feature nodulose or spinose basidiospores and belong to the Inocybe clade. The remaining four species are characterized by the combination of smooth spores and absence of pleurocystidia. Two of these share an alliance with the Pseudosperma clade, and the other two with the Inosperma clade. All 11 species likely share an ecological association with lowland tropical Dipterocarpaceae. The new combination I. mucidiolens is made (formerly I. calamistrata var. mucidiolens).

Introduction

The family Inocybaceae Jülich is a species-rich group of Agaricales (Basidiomycota) with some 700 species worldwide (Matheny et al. 2009). Species in the family can be recognized by their typically small but fleshy basidiomes, often with a dry, fibrillose, rimose or squamulose pileus, growth typically on soil, and yellowish brown basidiospores that lack a germ pore. The Inocybaceae occurs worldwide forming ectomycorrhizal (ECM) associations with numerous families of angiosperms and gymnosperms (Pinaceae, Gnetum) in tropical and temperate areas making it one of most diverse families of Agaricales (Kirk et al. 2008).

Species of Inocybe (Fr.) Fr. are poorly known in the tropics and elsewhere (Matheny et al. 2009, Bougher et al. 2012, Matheny et al. 2012a). Indeed, new taxa continue to be described from northern Europe, regions where the genus has been studied for some two hundred years (Kokkonen and Vauras 2012). In India, the genera Inocybe and Auritella Matheny & Bougher have thus far been recorded, but the family as a whole is poorly known in tropical regions of Asia. Despite this, India appears to be phylogenetically diverse in Inocybaceae containing lineages from six of seven major clades in the family (Matheny et al. 2009, 2012b). Only the genus Tubariomyces Esteve-Rav. & Matheny (Inocybaceae) has yet to be reported from India (Matheny et al. 2012b). Few Indian species, however, have been documented formally thus far (Horak 1981, Manjula 1983, Pradeep et al. 1996, Vrinda et al. 1997a, b, 1999, 2000, 2001, Natarajan et al. 2005, Matheny et al. 2012b, Farook et al. 2013, Latha and Manimohan 2015). The present study aims to clarify the taxonomic status of 11 species of Inocybe collected in a tropical region of India in the state of Kerala, all of which putatively form ECM associations with plant species of the family Dipterocarpaceae. Seven of these 11 taxa are described here as new, and one species is validated.

The state of Kerala lies along the southwest corner of peninsular India between 8°18′ and 12°48′ north latitudes and 74°52′ and 72°22′ east longitudes. It is situated between the Arabian Sea of the Indian Ocean to the west and the Western Ghats to the east, has an area of 38,864 sq km, which amounts to 1.2 % of the total geographic area of India. Situated along the west coast region of India, Kerala has a tropical climate with varied topographical features, high rainfall, and geographical conditions that favor the formation of highly diversified ecological niches. Most of the forested areas of the state are part of the Western Ghats, one of the mega diversity centers in India and a biodiversity hotspot. The forests of Kerala are considered very rich in species diversity and endemism. The state harbors 4694 taxa of flowering plants, of which 237 are endemic (Nayar et al. 2008), which is primarily due to the highly diversified ecological niches that occur from sea level to 2695 m above sea level. Champion and Seth (1968) recognize 26 forest types in Kerala, of which the major ones are west coast tropical evergreen, southern moist deciduous, dry mixed deciduous, subtropical hill forest, shola forest, southern mountain wet temperate grassland, mangroves, Myristica swamp forests, sub tropical hill savanna, and moist teak forests. The climate of Kerala is mainly wet and maritime tropical and heavily influenced by the seasonal monsoonal rains.

Materials and methods

Field collection and morphological analysis

Collections were studied using standard procedures for morphological examination of agarics. Gross morphological descriptions are based exclusively on fresh materials collected by the authors. Microscopic characters were studied on dried material using hand cut sections of basidiomes revived in a 3 % solution of KOH and examined under a Leica DME1000 compound microscope. Sections were stained with 1 % aqueous solution of Congo red and mounted in 3 % aqueous KOH. For evaluation of the range of spore size, 20 basidiospores were measured from each collection cited. Measurements of basidiospores include nodules, if present. Color notations refer to Kornerup and Wanscher (1978). Holotypes of newly described species are deposited at the University of Tennessee (TENN), and isotypes and paratypes examined are deposited at the Mycological Herbarium of Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Trivandrum (TBGT). Herbarium designations follow Thiers [continuously updated].

DNA extraction, PCR, and sequencing

DNA was extracted from dried basidiomes following protocols in Baroni and Matheny (2011). Procedures for PCR, PCR purification, and sequencing preparation are provided in Judge et al. (2010). Gene regions examined during this study include the internal transcribed spacer 1, 5.8S ribosomal RNA gene, and internal transcribed spacer 2 (ITS) of the nuclear ribosomal RNA operon, the 25S rRNA gene that encodes the nuclear large subunit ribosomal RNA (nLSU), and the region between conserved domains 6 and 7 of the rpb2 gene, which encodes the second largest subunit of RNA polymerase II. Primers used for PCR and direct sequencing are cited in these works (Matheny 2005, Judge et al. 2010, Baroni and Matheny 2011). DNA sequences were annotated using Sequencher 5.0.1 (Gene Codes Corporation, Ann Arbor, MI, USA).

Molecular analyses

Thirty-four DNA sequences (nLSU, ITS, rpb2) were generated for this study. BLASTn searches of all gene regions were performed on GenBank. Based on BLASTn results, sequences were manually aligned in five different matrices in MacClade (Maddison and Maddison 2005) and subjected to maximum likelihood (ML) phylogenetic analyses following procedures outlined in Baroni and Matheny (2011). RAxML v7.2.8 (Stamatakis 2006) was used to reconstruct phylogenetic trees bootstrapped with 1000 replicates. Data sets were partitioned by gene region. Outgroups for each matrix were designated based on more inclusive published phylogenetic results (Matheny et al. 2009, Matheny et al. 2012b, Horak et al. 2015). DNA alignments are available by request from the last author. Taxa used and GenBank accession numbers are provided in Table 1 (herbaria where specimens are deposited are indicated where known). In cases where specific subclade groupings were ambiguous (viz, I. albonitens, I. parvisquamulosa), we report the BLASTn results here, make assignment to a major clade per Matheny (2009), and predict any finer scale phylogenetic resolution.

Table 1 Taxon sampling and DNA sequences used for BLASTn and/or phylogenetic analyses

Taxonomy

Inocybe papilliformis C.K. Pradeep & Matheny, sp. nov. Figs. 1 and 16a–b.

Fig. 1

Inocybe papilliformis (TENN070303). a hymenial cystidia. b spores. c caulocystidia. d cauloparacystidia. Scale bars = 10 μm

Fig. 2

Inocybe hydrocybiformis (TENN070304). a spores. b basidia. c cheilocystidia. d caulocystidia. Scale bars = 10 μm

Fig. 3

ML tree showing phylogenetic placement of Indian I. papilliformis sp. nov. and I. hydrocybiformis (in bold). Numbers above and below branches indicate bootstrap support >70 %. The data set includes three gene regions (ITS, nLSU, rpb2) and 2828 nucleotide sites, of which 2808 were used in the phylogenetic analysis. Inocybe lasseri and Inocybe sp. ECV3648 were used for rooting purposes

Fig. 4

Inocybe parvisquamulosa (TENN070305). a, b. hymenial cystidia. c, d. spores. Scale bars = 10 μm

Fig. 5

Inocybe pileosulcata (TENN070306). a spores b hymenial cystidia. c basidium. d caulocystidia. Scale bars = 10 μm

Fig. 6

Inocybe rimulosa (TENN070307). a spores. b cheilocystidia. c, d caulocystidioid elements. Scale bars = 10 μm

Fig. 7

Inocybe alboflavella (TENN070309). a cheilocystidia. b spores. c caulocystidia. Scale bars = 10 μm

Fig. 8

ML tree showing phylogenetic placement of Indian I. rimulosa and I. alboflavella (in bold). Numbers above and below branches indicate bootstrap support >70 %. The data set includes two gene regions (nLSU, rpb2) and 2150 nucleotide sites, all of which were included in the phylogenetic analysis. The tree was rooted with Australian taxa of the Inosperma clade (I. viridipes ined.) and Mallocybe clade (I. isabellina ined., I. sabulosa ined., and I. subflavospora ined). The outgroups are pruned from the tree figure

Fig. 9

Inocybe carnosibulbosa (TENN070310). a–c cheilocystidia. d spores. Scale bars = 10 μm

Fig. 10

Inocybe albonitens (TENN070311). a basidia. b spores. c hymenial cystidia. d pileipellis. e caulocystidia. Scale bars = 10 μm

Fig. 11

Inocybe flavosquamulosa (TENN070312). a cheilocystidia with paracystidia. b pleurocystidia. c spores. d caulocystidia with paracystidia. Scale bars = 10 μm

Fig. 12

ML tree showing phylogenetic placement of Indian I. flavosquamulosa and I. purpureoflavida (in bold). Numbers above and below branches indicate bootstrap support >70 %. The data set includes three gene regions (ITS, nLSU, rpb2) and 2737 included nucleotide sites. The tree was rooted with I. conspicuospora and Inocybe sp. PC96039 based on Matheny et al. (2009)

Fig. 13

Inocybe purpureoflavida (TENN070313). a spores. b hymenial cystidia. c pileipellis. d caulocystidia. Scale bars = 10 μm

Fig. 14

Inocybe virosa (TENN070314). a spores. b cheilocystidia. Scale bars = 10 μm

Fig. 15

ML tree showing phylogenetic placement of Indian I. virosa and I. carnosibulbosa (in bold). Numbers above and below branches indicate bootstrap support >70 %. The data set includes two gene regions (nLSU, rpb2) and 2167 nucleotide sites, all of which were included in the phylogenetic analysis. The tree was rooted with Tubariomyces based on Matheny et al. (2012b)

Fig. 16

Habit in situ. a, b Inocybe papilliformis (TENN070303). c, d. I. hydrocybiformis (TENN070304). e I. parvisquamulosa (TENN070305). f I. pileosulcata (TENN070306). g I. rimulosa (TENN070307). Scale bars = 10 mm

MycoBank: MB 813813

Diagnosis: Most similar to Inocybe hydrocybiformis and I. petchii but differs by the combination of very large basidiospores (15–19.5 × 14–18 μm), thin and small basidiomes, pileus with acute papillate umbo, and metuloid cheilocystidia and pleurocystidia. Phylogenetic placement: Inocybe clade.

Holotype: India, Kerala State, Wayanad District, Ponkuzhy, 15 Aug 2007, TENN070303 (GenBank accession no. KP171131-ITS, KP170912-nLSU, KM245988-rpb2); isotype TBGT10480.

Etymology: papilliformis, in reference to the acute or papillate umbo on the pileus

Pileus 4–20 mm wide, conic, convex, campanulate (in some specimens) with acute papillate umbo; surface uniformly brown (5F8) or with some shade of brown (5C4–5, 5D5, 6B3, 6C3, 7E4), appressed squamulose especially near the disc, smooth when young, striate up to the disc, hygrophanous, dry; margin straight, entire to incised. Lamellae adnexed, raw umber (5F8, 5C3, 5D4, 6D3), up to 2 mm deep, close with lamellulae of different lengths; edges concolourous with the sides or whitish, entire to naked eye. Stipe 18–110 × 0.5–3 mm, central, cylindric, narrowly tapering up from a slightly broad base (not marginate), narrowly hollow, brittle; brown (5F8, 5C4, 6E7); surface floccose squamulose becoming smooth. Context brown or pale, thin, soft. Odor mildly acidic.

Basidiospores 15–19.5 × 14–18 μm, avL = 17.5, avW = 15.8, Q = 1–1.14, avQ = 1.10, globose to subglobose, spinose with conic nodules, these often bifid or saddle shaped, yellowish brown, apiculus prominent and distinct. Basidia 22–35 × 10–13 μm, clavate, 4-spored, rarely 2-spored. Lamella edge crowded with cystidia. Cheilo- and pleurocystidia 25–46 × 10–23 μm, fusoid to lageniform, thick-walled, with small crystals at the apex, hyaline. Hymenophoral trama regular, hyphae 5–10 μm wide, thin-walled, hyaline. Subhymenium pseudoparenchymatous, 2–3 cells thick. Pileal trama composed of hyphae 7–15 μm wide, inflated, thin-walled, with yellowish brown contents. Pileipellis a cutis, rarely disrupted at the disc, hyphae 3–8 μm wide, incrusted with yellowish brown contents. Stipitipellis a cutis of parallel hyphae, incrusted 2.5–6.5 μm wide, with pale yellowish brown contents. Caulocystidia 32–55 × 10–17 μm, similar to hymenial cystidia, abundant, present on the upper part, absent elsewhere, intermixed with thin-walled cauloparacystidia. Cauloparacystidia 16–30 × 8–16 μm, clavate, cylindro-clavate, thin-walled, hyaline, crowded at the base of caulocystidia. Clamp connections present in all parts.

Habit and habitat: Solitary, scattered, or in groups or in pairs on riverine sandy soil under Hopea parviflora and Vateria indica (Dipterocarpaceae) trees.

Additional specimens examined: India, Kerala State, Trivandrum District, JNTBGRI campus: 4 Aug 1994, TBGT1300; 5 Aug 1994, TBGT1315; 5 Dec 1996, TBGT3712; 18 Jul 1997, TBGT1101; 7 Aug 2003, TBGT6448; 13 Jul 2004, TBGT7489; 10 Jun 2008, TBGT11044; 31 May 2011, TBGT13609; 2 Jun 2011, TBGT13617; 15 Jul 2011, TBGT13686; 8 Aug 2013, TBGT14771; Trivandrum District, Kallar, 7 Aug 2008, TBGT11651; 29 Oct 2008, TBGT12145; Ernakulam District, Iringole, 6 Jul 2004, TBGT7413; Wayanad District, 8 Nov 2007, TBGT10749; 16 Jul 2008, TBGT11413; 24 Sep 2008, TBGT11988; 23 Jul 2013, TBGT14746.

Discussion: Inocybe papilliformis is superficially related to a number of species in some macro- and micro-morphological features. These include Inocybe petchii Boedijn (Pegler 1986; Horak et al. 2015), I. calospora Quél. (Vauras 1989), I. echinosimilis (E. Horak) Garrido, I. gemina (E. Horak) Garrido, I. hydrocybiformis (Corner & E. Horak) Garrido (Horak 1979; Horak et al. 2015), and I. stellata E. Horak, Desjardin & Matheny (Horak et al. 2015). However, I. papilliformis is distinguished by one or other characters and also molecularly. The distinctive features of the Indian taxon include: the small, thin, conico-convex, brown but hygrophanous pileus (which never becomes plane), presence of an acute papillate umbo; slender, long fragile stipe without a marginate basal bulb; mild acidic odor; and very large globose to subglobose spinose basidiospores with conic nodules that are often bifid or saddle-shaped.

Inocybe petchii (originally described as Inocybe umbonata Petch, non Quél.) was first recorded from Sri Lanka and appears most similar to I. papilliformis. Both species share the similarly sized and very large basidiospores, but basidiomes of I. petchii are more robust, the stipe is red brown and entirely pruinose and features a bulbous submarginate base (Horak et al. 2015). Though thought to be widespread in southeast Asia, molecular data for I. petchii are lacking for a more thorough comparison. Inocybe acutata Takahito Kobayashi & Eiji Nagasawa (Kobayashi 1993) originally described from Japan is also closely related to the present species. However, differs mainly by its smaller subglobose spiny spores (8.2–10.4 × 7.6–10.2 μm), lack of pleurocystidia and presence of rather abundant paracystidia. Inocybe papilliformis is phylogenetically most closely related to Thai and Indian specimens of I. hydrocybiformis (Fig. 3), documented below, which is characterized by its smaller spores, the thin-walled, yellow-pigmented (non-metuloid) cheilocystidia and absence of pleurocystidia.

Inocybe hydrocybiformis (Corner & E. Horak) Garrido, Biblioth. Mycol. 120: 176, 1988 Figs. 2 and 16c–d

Astrosporina hydrocybiformis Corner & E. Horak, Persoonia 10: 170 1979.

Pileus 4–15 mm wide, conic when young becoming convex to plane, with or without a small obtuse, acute to subacute umbo; pastel yellow to light yellow (3A4–5, 4A4), uniformly so when young, becoming pale brown, oak brown, to brown (5D5–6, 6E4), remaining yellowish towards margin when mature, appressed fibrillose-squamulose throughout when young, squamules wearing away during heavy rain, and then becoming brown without the shade of yellow; margin straight, striate, or incised. Lamellae adnexed, brown (6E4, 6D4) up to 2 mm deep, close to subcrowded with lamellulae of different lengths; edges yellowish, entire. Stipe 25–35 × 0.5–3 mm, central, cylindric, equal or narrowly tapering up from a slightly enlarged base (not marginate); pastel yellow (3A4), appressed-squamulose entirely, squamules vanishing during rain or on handling and then becoming brown (5D6, 6E4). Context dull white to brown, soft. Odor mild, agreeable.

Basidiospores 9.5–13.5 × 7.5–13 μm, avL = 12.1, avW = 10.8, Q = 1–1.26, avQ = 1.12, stellate with many (10–16) conic to saddle shaped spines around a subglobose to globose outline, yellowish brown with a prominent hilar appendix. Basidia 28–46 × 12–14 μm, clavate, 4-spored, rarely 2-spored, thin-walled, hyaline. Lamella edge sterile with crowded cheilocystidia. Cheilocystidia 33–65 × 9–14 μm, cylindro-clavate, curved, often strangulated in the upper part, at times bifurcated at the apex, with dense yellowish refractive contents, thin-walled. Pleurocystidia absent. Hymenophoral trama regular, hyphae 7–13 μm wide, thin-walled, hyaline. Subhymenium pseudoparenchymatous. Pileal trama composed of hyphae 8–16(–21) μm wide, some inflated, thin-walled, hyaline. Pileipellis a cutis, rarely disrupted, hyphae 4–12 μm wide, incrusted with yellowish brown contents. Stipitipellis composed of parallel hyphae, 4–7 μm wide, incrusted, with pale yellowish brown contents. Caulocystidia 46–82 × 4–10 μm, occurring in clusters on the upper part of the stipe, absent from lower part, similar to cheilocystidia. Clamp connections and oleiferous hyphae present.

Habit and habitat: Scattered on forest floor or in riverine sandy soil under Hopea parviflora (Dipterocarpaceae), Garcinia gummigutta (Clusiaceae) and Holigarna arnottiana (Anacardiaceae) trees.

Specimens examined: India, Kerala State, Wayanad District, Muthanga, Ponkuzhy: 16 Jul 2008, TBGT11402; 24 Sep 2008, TBGT 11989; Trivandrum District, JNTBGRI campus, 5 Nov 2008, TBGT12204; 6 Nov 2008, TBGT12211; 11 Nov 2008, TBGT12238; 28 Nov 2008, TBGT12318 (TENN070304) (KP171130-ITS, KP17091-nLSU, KM245987-rpb2).

Discussion: The above description matches with the type description of Astrosporina hydrocybiformis from Singapore (Horak 1979) except for the presence of occasional 2-spored basidia and more strangulated, bifid or branched cheilocystidia present in the Indian collections. DNA sequence data from TBGT12318 support the designation of I. hydrocybiformis to our material due to the very high ITS similarity (99 % similarity) and phylogenetic affinity to a collection under this name from Thailand (Horak et al. 2015; Fig. 3). Indian collections feature the characteristic spinose basidiospores, thin-walled yellow-pigmented cheilocystidia, and absence of pleurocystida. Despite this latter feature, the species is a confirmed member of the Inocybe clade (Horak et al. 2015). This species was previously reported from Kerala by Vrinda et al. (1999).

Inocybe parvisquamulosa C.K. Pradeep & Matheny, sp.nov. Figs. 4 and 16e

MycoBank: MB 813814

Diagnosis: Similar to Inocybe brevisquamulosa described from Thailand in dipterocarp forests, but differs by larger basidiomes, larger basidiospores, and ITS divergence (5 %). Phylogenetic placement: Inocybe clade.

Holotype: India, Kerala State, Trivandrum District, JNTBGRI campus, 26 Nov 2008, TENN070305 (GenBank accession no. KT329447-ITS, KT329453-nLSU, KT329442-rpb2); isotype TBGT12303

Etymology: parvus (little), squamulosus (minutely scaly)

Pileus 7–35 mm wide, convex, plano-convex to applanate or becoming slightly uplifted in age, at times with a broad obtuse umbo; brown or with some shade of brown (6F4, 6E4–6, 6D4–6, 5D4–7) or slightly paler; surface fibrillose striate becoming squamulose towards the disc, rimose towards margin; margin straight, entire to incised. Lamellae adnexed, brown (6E4–5, 6D4) up to 4 mm deep, crowded with lamellulae of different lengths; edges concolourous with the sides, entire. Stipe 20–50 × 2–5 mm, central, cylindric, curved, equal or narrowly tapering up from a slightly broad base (not marginate), stuffed becoming hollow; dull white when young becoming brownish (5D4/5D5/6E5), fibrillose-striate, dry. Context dull white, thin, soft. Odor none. Basidiomes small to medium.

Basidiospores(8–)9–12(–13) × (6.5–)7.5–10.5(–11) μm, avL = 10.4, avW = 8.7, Q = 1.06–1.27, avQ = 1.19, distinctly nodulose or almost stellate, subglobose to broadly ellipsoid or ellipsoid in outline, with many (8–14) conic or obtuse nodules, yellowish brown. Basidia 28–34 × 11–12 μm, clavate, 4-spored, thin-walled, hyaline. Cheilo- and pleurocystidia 39–50 × 10–19 μm, fusoid, lageniform, thick-walled, metuloidal with crystals at the apex, yellowish brown. Hymenophoral trama regular, hyphae 6–12 (–14) μm wide, cylindric to inflated, thin-walled, hyaline. Subhymenium pseudoparenchymatous, 3–4 cells thick. Pileal tramal hyphae 7.5–17.5(–30) μm wide, at times inflated, thin-walled, hyaline. Pileipellis a cutis, rarely disrupted at the disc, hyphae 8–16 μm wide, incrusted with yellowish brown contents. Stipitipellis a cutis of parallel hyphae, incrusted, 2.5–5.5 μm wide, with pale yellowish brown contents. Caulocystidia none. Clamp-connections present in all tissues.

Habit and habitat: Solitary, scattered, in pairs or in groups on forest floor under Hopea parviflora, Vateria indica (Dipterocarpaceae), Garcinia sp. (Clusiaceae) or Diospyrus montana (Ebenaceae) trees in India. Recorded under Dipterocarpus alatus in Thailand.

Additional specimens examined: India, Kerala State, Trivandrum District, JNTBGRI campus, 5 Nov 2008, TBGT12198; 6 Nov 2008, TBGT12212; 25 Nov 2008, TBGT12296; 27 Nov 2008, TBGT12313; 28 Nov 2008, TBGT12326.

Discussion: Inocybe parvisquamulosa is a new species very similar to I. brevisquamulosa E. Horak, Matheny & Desjardin recently described from tropical dipterocarp forests in Thailand (Horak et al. 2015). The Indian species shares many features in common with I. brevisquamulosa including the squamulose pileus disc, fibrillose and non-pruinose stipe surface, lack of an odor, distinctly nodulose spores, absence of caulocystidia, and ectomycorrhizal association with dipterocarps. Inocybe parvisquamulosa differs from I. brevisquamulosa by its larger basidiomes (the pileus of the latter reaches only up to 10 mm wide and the stipe up to 1–1.5 mm thick), larger spores (8.5–10 × 5.5–6 μm in I. brevisquamulosa), and molecular sequence divergence (ITS 5 % dissimilar). Phylogenetically, I. brevisquamulosa appears to be sister to the I. calospora group, but this result is weakly supported (Horak et al. 2015). Thus, we consider the placement of I. brevisquamulosa and I. parvisquamulosa as incertae sedis within the Inocybe clade.

Inocybe parvisquamulosa has also been recorded from Thailand based on high (99 %) ITS similarity to a sequence (AB854670) produced from basidiomes sampled under Dipterocarpus alatus after a GenBank BLASTn search.

Inocybe pileosulcata E. Horak, Matheny & Desjardin, Phytotaxa 230: 227. 2015. Figs. 5 and 16f

Pileus 16–35 mm wide, convex, plano-convex to applanate, often uplifted in old ones, rarely with a broad obtuse umbo; surface dark brown to brownish grey (6F7–8) at centre and brown (6E4–5) elsewhere, smooth at centre, fibrillose-striate, rimose towards margin, splitting like the spokes of a wheel exposing the yellowish white (4A2) context below, dry; margin straight, entire to incised. Lamellae adnexed, yellowish white, reddish blonde, dark blonde or café-au-lait (4A2, 5C4, 5D4, 6D3), subdistant with lamellulae of different lengths; edges concolourous with the sides, entire. Stipe 23–44 × 2–4 mm, central, cylindric, solid, slightly curved, narrowly tapering up from a slightly broad marginate base; pale orange to orange white (5A2–3), becoming darker on handling; surface pruinose throughout; veil none. Context white, thin, up to 2 mm thick, soft. Odor none.

Basidiospores 9.5–11(12) × 8–9.5(10) μm, avL = 10.4, avW = 8.9, Q = 1.08–1.36, avQ = 1.16, subglobose, stellate, with more than 11 conspicuous obtuse knobs, yellowish brown. Basidia 25–41 × 9–12 μm, clavate, 4-spored. Lamella edge crowded with paracystidia intermingled with basidia and metuloids. Paracystidia 15–27 × 7–12 μm, clavate, thin-walled, hyaline. Metuloids abundant on both sides and edges of lamellae, 45–70 × 16–23 μm, ventricose fusoid, thick-walled, yellowish brown with crystals at apices. Hymenophoral trama regular, hyphae 3–13 μm wide, at times inflated to 24 μm wide, thin-walled, hyaline. Subhymenium pseudoparenchymatous, well developed 2–4 cells thick. Pileal tramal hyphae 18–34 μm wide, inflated, thin-walled, hyaline. Pileipellis a cutis of radially arranged hyphae 5–12 μm wide, incrusted with yellowish brown contents. Stipitipellis a cutis of parallel hyphae, these incrusted 3–10 μm wide, with pale yellowish brown contents. Caulocystidia 54–63 × 17–26 μm, ventricose fusoid, thick-walled, yellowish with crystals at apices, abundant, present throughout the stipe, but more frequent on the upper part. Cauloparacystidia 15–22 × 9–14 μm, clavate, thin-walled, crowded at the base of the metuloid caulocystidia. Clamp connections and oleiferous hyphae present.

Habit and habitat: Scattered on riverine sandy soil under Hopea parviflora (Dipterocarpaceae).

Specimens examined: India, Kerala State, Wayanad District, Ponkuzhy, 7 Nov 2007, TBGT10742 (TENN070306) (GenBank accession no. KP308810-ITS, KP170979-nLSU, KM406218-rpb2); 8 Nov 2007, TBGT10754. Thailand. Chiang Mai Province, Highway 1095 at 22 km marker, 750 m elev., on soil in tropical submontane forest dominated by Dipterocarpus, 11 Jun 2006, DED8058 (holotype).

Discussion: Inocybe pileosulcata is best characterized by the combination of brown splitting fibrillose striate pileus, marginate stipe base, subglobose stellate spores, abundant caulocystidia, and association with Dipterocarpaceae in India and Thailand. DNA sequences (ITS, nLSU, rpb2; Data not shown) of Indian material are virtually identical to the type (DED8058, SFSU) and other collections of I. pileosulcata described from Thailand (Horak et al. 2015), where it occurs in lowland and montane tropical forests dominated by Dipterocarpaceae. Inocybe miyiensis T. Bau & Y.G. Fan (Fan and Bau 2014), a recently described species from subtropical China differs by its straw yellow pileus, 2- spored basidia and its apparent association with Quercus. The species is allied phylogenetically with I. asterospora Quél. group (Inocybe clade) and most closely related to two Australasian species, I. vagata Matheny & Bougher and I. nobilissima Matheny & Bougher, and I. insignis A.H. Sm. from North America (Matheny and Bougher 2015). Inocybe pileosulcata differs most readily from these and other species by geographic location (tropical Southeast Asia) and association with Dipterocarpaceae.

Inocybe rimulosa C.K. Pradeep & Matheny, sp. nov. Figs. 6 and 16g

MycoBank: MB 813815

Diagnosis: Pileus smooth, rimose, dark brown at the center, light brown towards the margin. Lamellae without olivaceous tones. Stipe white to cream, becoming brown on handling, not smooth, not scaly. Odor mild. Closely related to the tropical Australian species Inocybe gracilissima but differs by the absence of olivaceous tones on the pileus and non-conical pilei when young. Phylogenetic placement: Pseudosperma clade.

Holotype: India, Kerala State, Trivandrum District, JNTBGRI campus, 17 Aug 2009, TENN070307 (GenBank accession no. KP636860-ITS, KP171059-nLSU, KM656098-rpb2); isotype TBGT12854

Etymology: rimulosus, having small cracks

Pileus 10–35 mm wide, convex when young, becoming plano-convex to plane with a small obtuse umbo; brown or “titian red” (7D6), dark brown (7F8, 7F5, 8F6), or some shade of brown (6D4–5, 7E4–7, 7D5, 7E4) at centre, light brown (6C4–5, 7E5) towards the margin; surface dry, smooth at the center, fibrillose striate near the margin, rimose, often splitting radially to expose the underlying white context; margin incurved when young becoming straight, rarely uplifted, entire to incised. Lamellae adnexed, brownish orange, clay, dark blond, camel, greyish orange (5C3, 5D4–5, 6D4, 5B3), up to 3 mm deep, close with lamellulae of different lengths; edges whitish, entire. Stipe 18–50 × 1–4 mm, central, cylindric, equal, narrowly tapering up from a broad non-marginate base; white, cream, becoming brownish on handling (6C4, 6D4), pruinose throughout, denser at upper part. Context hollow, white, thin, soft. Odor mild, not diagnostic.

Basidiospores 9–13 × 5.5–6.5 μm, avL = 11.2, avW = 6, Q = 1.44–2.28, avQ = 1.84, smooth, ovoid-ellipsoid, elongate ellipsoid, phaseoliform, yellowish brown. Basidia 18–30 × 8.5–10 μm, clavate, 4-spored with contents. Lamella edge sterile with crowded cheilocystidia. Cheilocystidia 18–58 × 10–15 μm, clavate, cylindro-clavate, lageniform, rarely bifid at apex, often with a pedicel, tramal in origin, thin-walled, hyaline. Pleurocystidia absent. Hymenophoral trama regular, hyphae 2.5–15 μm(–23) wide, cylindric to inflated, thin-walled, hyaline. Subhymenium pseudoparenchymatous, 2–3 cells thick. Pileal tramal hyphae 4–29 μm wide, inflated, thin-walled, hyaline. Pileipellis a cutis, hyphae 3–11 μm wide, incrusted with brown contents. Stipitipellis a cutis of parallel hyphae, 5–10 μm wide, incrusted, thin-walled, hyaline. Stipitipellis hyphal ends project out as cystidioid elements on the upper part, 22–93 × 7.5–9 μm, cylindro-clavate, thin-walled, hyaline. Clamp-connections present in all tissues.

Habit and habitat: Solitary, scattered, or in groups or in pairs on soil under Hopea parviflora, Vateria indica (Dipterocarpaceae), Calophyllum (Calophyllaceae), and Myristica (Myristicaceae) trees.

Additional specimens examined: India, Kerala State, Trivandrum District, JNTBGRI campus, 6 Aug 2009 TBGT12828 (TENN070308) (GenBank accession no. KP636861-ITS, KP171060-nLSU, KM656099-rpb2), 6 Aug 2009 TBGT12829; 7 Aug 2009, TBGT12832; 18 Aug 2009, TBGT12861; 19 Aug 2009, TBGT12870; 17 Sep 2009, TBGT12922; 22 Sep 2009, TBGT12931.

Discussion: Inocybe rimulosa is a member of the Pseudosperma clade and most closely related to a tropical Australian species, I. gracilissima Matheny & Bougher ined., and an undescribed species from eastern North America (Fig. 9). Aside from geographic location and differences in plant associates, I. rimulosa differs from these species by its convex to plane pileus (deeply conical when young in I. gracilissima) and absence of olivaceous tones.

Other tropical species with affinities to the Pseudosperma clade have yet to be placed phylogenetically and presently lack DNA sequences for comparison. These include I. littoralis Pegler and I. ingae Pegler (Pegler 1983) described from the neotropics and I. cutifracta Petch (Pegler 1986) described from Sri Lanka. Inocybe littoralis is characterized by its amber yellow pileus, subreniform basidiospores, clavate cheilocystidia, and absence of caulocystidia. Inocybe ingae is distinguished by its small thin basidiomes, cream silky fibrillose pileus with an acute umbo, white stipe, and inflated clavate cheilocystidia. Inocybe cutifracta differs from I. rimulosa by its smaller spores and distinct capitate cheilocystidia. None of the Indomalayan and Australasian species documented by Horak (1980) matches the present species. Both I. littoralis and I. ingae have been reported from India (Farook et al. 2013), but in our opinion the application of neotropical names to paleotropical taxa is highly doubtful. The recently described Inocybe keralensis K.P.D. Latha & Manim. (Latha and Manimohan 2015) differs by its yellowish brown, appressed fibrillose pileus, adnate to emarginate lamellae, brown fibrillose stipe, smaller spores, encrusted thick-walled cheilocystidia and a duplex pileipellis. Unfortunately the sequences are not available on GenBank for comparison.

Inocybe alboflavella C.K. Pradeep & Matheny, sp. nov. Figs. 7 and 17b, c

Fig. 17

Habit in situ. a Inocybe flavosquamulosa (TENN070312). b, c. I. alboflavella (TENN070309). d, f. I. carnosibulbosa (TENN070310). e, g I. albonitens (TENN070311). h I. virosa (TENN070314). i I. purpureoflavida (TENN070313). Scale bars = 10 mm

MycoBank: MB 813816

Diagnosis: Differs from similar tropical and neotropical species of the Pseudosperma clade by small yellowish white basidiomes, large variable spores, cylindro-clavate and septate cheilocystidia, lack of pleurocystidia and caulocystidia, and mycorrhizal host. Phylogenetic placement: Pseudosperma clade.

Holotype: India, Kerala State, TBGRI campus, 3 Jul 2008, TENN070309 (GenBank accession no. KP636859-ITS, KP171058-nLSU, KM656097-rpb2); isotype TBGT11280.

Etymology: albus (white), flavellus (pale yellow), in reference to the yellowish white pileus.

Pileus 7–20 mm wide, convex becoming plane with a small obtuse umbo, rarely without umbo; white, cream, yellowish white, putty (2A2, 4A2–3, 4B2, 5C4–5), becoming pale brown in old specimens; surface dry, not scaly, but covered with white silky fibrils over the center, elsewhere silky fibrillose striate, splitting radially to expose the underlying white context below, becoming rimose towards margin; margin straight, entire to incised, rarely appendiculate when young. Lamellae adnexed, cream becoming dark blonde (4A3, 5C4, 5D4), narrow, up to 2 mm deep, close to subcrowded with lamellulae of different lengths; edges whitish, fimbriate. Stipe 10–35 × 1–3 mm, central, cylindric, solid, equal, slightly tapering up from a slightly swollen base, non-marginate; cream, flocculose-fibrillose throughout, more so on the upper half, squamules vanishing on handling. Context white, thin, soft. Odor mild.

Basidiospores (7–)8–12(13) × 5–7 μm, avL = 10.2, avW = 5.9, Q = 1.35–2.06, avQ = 1.71, smooth, highly variable in shape and size, within a single specimen, ellipsoid to elongate, phaseoliform, thick-walled, pale yellowish (in KOH), rarely with an apical thinning. Basidia 23–40.1 × 9–13 μm, clavate, 4-spored, rarely 1, 2-spored, thin-walled, hyaline. Lamella edge sterile with crowded cheilocystidia. Cheilocystidia 12–59 × 7–20 μm, clavate, cylindro-clavate, mostly septate (1, 2), thin-walled, hyaline, rarely with oleaginous contents, tramal in origin. Pleurocystidia absent. Hymenophoral trama regular, hyphae 3–33 μm wide, cylindric to inflated, thin-walled, hyaline. Subhymenium pseudoparenchymatous. Pileal tramal hyphae thin-walled, hyaline, 4.5–32 μm wide, inflated. Pileipellis an epicutis of radially arranged hyphae, these 4–14 μm wide, incrusted with yellowish contents. Stipitipellis a cutis of parallel hyphae 4–13 μm wide, incrusted, with pale yellowish contents. Caulocystidia 13–63 × 5–16 μm, cylindro-clavate to clavate, thin-walled, incrusted, hyaline, moderately abundant. Clamp connections and oleiferous hyphae present.

Habit and habitat: Solitary or scattered on soil under Vitex altissima (Lamiaceae) and nearby dipterocarps.

Additional specimens examined: India, Kerala State, TBGRI campus, 11 Nov 2007, TBGT12237; 24 Jun 2008, TBGT11225; 3 Jul 2008, TBGT11290; 4 Aug 2010, TBGT13412; 26 Oct 2010, TBGT13522; 28 Jun 2011, TBGT13671; 22 Sep 2011, TBGT13822; 7 Nov 2013, TBGT14864; 21 Nov 2013, TBGT14886.

Discussion: Inocybe alboflavella is placed phylogenetically in the Pseudosperma clade, where it occupies an isolated position, most closely related with strong support to an unidentified species from Castanopsis forest in Papua New Guinea (Fig. 8). Morphological data support placement in the Pseudosperma clade as I. alboflavella features traits typical of species in this group: the rimose pileus, coarsely fibrillose stipe covering, unchanging colors of the context, smooth spores, and absence of pleurocystidia. Some of the unique features of I. alboflavella include the white silky fibrils over the disc and yellowish pileal margin, absence of any odor, and potential association with trees of the Lamiaceae and/or Dipterocarpaceae.

Allied species from other tropical areas include I. littoralis Pegler and I. ingae Pegler (Pegler 1983). The former differs from I. alboflavella by its slightly larger basidiomes with an amber yellow pileus, ellipsoid to subreniform spores, absence of caulocystidia, and association with Coccoloba (Polygonaceae) in the neotropics. Inocybe ingae is another neotropical species characterized by its acutely umbonate and pale ochraceous pileus, smaller spores, absence of caulocystidia, and association with trees of the genus Inga.

Inocybe carnosibulbosa C.K. Pradeep & Matheny sp. nov. Figs. 9 and 17d, f

MycoBank: MB 813817

Diagnosis: Distinct from all species in the Inosperma clade by large, fleshy, tricholomatoid basidiomes, bicolorous pileus when mature, stipe with a large pronounced basal bulb, subglobose or broadly ellipsoid basidiospores, absence of pleurocystidia, and septate cheilocystidia with long narrow neck reaching lengths >100 μm. Phylogenetic placement: Inosperma clade, “Old World Tropical clade 2”.

Holotype: India, Kerala State, Trivandrum District, JNTBGRI campus, 25 Sep 2008, TENN070310 (GenBank accession no. KT329448-ITS, KT329454-nLSU, KT329443-rpb2); isotype TBGT12047

Etymology: carnosus (fleshy), bulbosus (bulbous), in reference to the large fleshy basidiomes with a pronounced bulbous stipe base

Pileus 45–105 mm wide, convex when young, becoming plano-convex to applanate with a broad obtuse umbo or slightly depressed at centre become slightly uplifted with age; uniformly yellowish white to cream (3A2, 4A3) when young, becoming more brownish over the disc (6C3–4, 6D4, 6E5–6) and cream to yellowish white (4A2–3) elsewhere, thus becoming bicolorous; surface dry, appressed fibrillose striate except at the disc that is smooth and unbroken, becoming squamulose when dry or rimose, often splitting radially exposing the underlying white context; margin incurved when young becoming straight, entire to incised. Lamellae adnexed, white to yellowish white when young, becoming brownish orange (5C3–4) with age, up to 14 mm deep, crowded, lamellulae of different lengths; edges paler, entire. Stipe 50–120 × 7–17 mm, central, cylindric, with or without a marginate bulbous base tapering abruptly below; white to yellowish white (5A2–3), become brownish on handling (6C4, 6D4, 6F4), fibrillose striate. Context solid, white, soft. Odor mild. Basidiomes thick, fleshy, tricholomatoid.

Basidiospores (5.5–)6–8 × 5–6.5 μm, avL = 7.1, avW = 5.6, Q = 1.07–1.42 avQ = 1.26, smooth, subglobose to broadly ellipsoid, rarely phaseoliform, yellowish brown, thick-walled. Basidia 27–31 × 7–8 μm, clavate, 4-spored, thin-walled, hyaline. Lamella edge sterile with tufts of cheilocystidia. Cheilocystidia 29–140 × 6–13 μm, clavate, vesiculose, lageniform with a long narrow neck, multi-septate, tramal in origin, thin-walled, hyaline. Hymenophoral trama regular composed of short to medium, thin-walled, hyaline hyphae, 5.5–14 μm wide. Subhymenium pseudoparenchymatous, 2–3 cells thick. Pileal trama composed of loosely arranged hyphae 2.5–12.5(–22) μm wide, inflated, thin-walled, hyaline. Pileipellis a cutis, interrupted at places, composed of parallel hyphae 3–5 μm wide, incrusted, with yellowish brown contents. Stipitipellis a cutis of parallel hyphae, these 2.5–5 μm wide, incrusted, thin-walled, hyaline. Caulocystidia absent. Clamp connections present in all tissues.

Habit and habitat: Scattered, in groups or in pairs on forest soil under Hopea parviflora (Dipterocarpaceae) and Xanthophyllum (Polygalaceae) trees.

Additional specimens examined: India, Kerala State, Trivandrum District, TBGRI campus, 20 Nov 2008, TBGT12276; 14 Oct 2009, TBGT12976; 23 Oct 2009, TBGT13011; 16 Nov 2011, TBGT13898; 17 Nov 2011, TBGT13906; 18 Nov 2011, TBGT13909; Trivandrum District, Ex-Service Colony, 20 Jul 2015, TBGT15769.

Discussion: Inocybe carnosibulbosa is distinguished by its large fleshy tricholomatoid basidiomes, cream to yellowish white pileus with a brownish disc, the stipe often with a marginate bulbous base, small subglobose to broadly ellipsoid smooth spores, presence of clavate to vesiculose septate cheilocystidia often with a long narrow neck, absence of pleurocystidia and caulocystidia, and association with Xanthophyllum and Hopea trees.

In gross morphology this can be compared to Inocybe perlata (Cooke) Sacc. (Vauras and Huhtinen 1986), I. umbrina Massee (Horak 1980) and I. rimosa (Bull.: Fr.) Kumm. (Kuyper 1986). All these species can be separated among other things by their larger spores, shorter clavate cheilocystidia, and different plant associates.

BLASTn results of nLSU and rpb2 sequences from TBGT12047 suggest this species is most closely related to but distinct from other species in the Inosperma clade. Indeed, I. carnosibulbosa shares its nearest phylogenetic affinities with several unclarified species from India, Thailand, and Papua New Guinea in “Old World tropical clade 2” recovered by Kropp et al. (2013) and shown in Fig. 15.

Specimens of I. carnosibulbosa (TBGT15769) were made at a local site after reports of human poisoning and the deaths of a cat and chicken after consumption of this species. The affected people were admitted to hospital and fully recovered.

Inocybe albonitens C.K. Pradeep & Matheny, sp. nov. Figs. 10 and 17e, g

MycoBank: MB 813818

Diagnosis: Most similar to but distinct from Inocybe alboviscida by the larger broadly ellipsoid to ellipsoid nodulose basidiospores, dipterocarp association, and occurrence in lowland tropical habitats.

Holotype: India, Kerala State, Wayanad District, Muthanga, 24 Sep 2008, TENN070311 (GenBank accession no. KT329449-ITS, KT329455-nLSU); isotype TBGT11987.

Etymology: albus (white), nitens (shining, greasy), in reference to the sticky white pileus

Pileus 8–30 mm wide, convex, plano-convex to uplifted with a small obtuse umbo; chalky white when young, which is smooth and glabrous, not striate, later becoming dull white to brownish orange (5C3) to slightly darker in old specimens; surface sticky when wet, sulcate-striate to plicate in dry weather; margin straight, entire, becoming rimose with age. Lamellae adnexed, off-white to birch gray (5C2) to brownish orange (6C3), up to 2 mm deep, crowded with lamellulae of different lengths; edges concolourous with the sides, entire in appearance. Stipe 15–46 × 1–4 mm, central, cylindric, tapering narrowly from a broad base; often with a rim at the base; surface white, smooth and glabrous but pruinose under lens. Context white, thin. Odor mildly spermatic.

Basidiospores 7.5–11 × 6–9.5 μm, avL = 9.3, avW = 7.4, Q = 1.05–1.62, avQ = 1.26, nodulose with 9–11 moderate-sized conical nodules about a broadly ellipsoid to ellipsoid (subglobose) outline, yellowish brown. Basidia 26–33 × 10–12 μm, clavate, 4-sterigmate, hyaline. Lamella edge heteromorphous. Cystidia present on both sides and edges of lamellae. Cystidia 47–82 × 19–28 μm, lageniform to subfusoid, mostly without a pedicel or rarely with a short pedicel, thick-walled, walls mostly 4–7 μm thick, hyaline with crystalline apex. Hymenophoral trama regular, hyphae 2–21 μm wide, thin-walled, hyaline. Subhymenium pseudoparenchymatous. Pileal trama of interwoven hyphae, these 2.5–21 μm wide, often inflated, thin-walled, hyaline. Pileipellis an interrupted ixocutis of gelatinized hyphae, 2–4 μm wide, thin-walled, hyaline. Stipe trama composed of parallel hyphae, these 4–18 μm wide, inflated, thin-walled, hyaline. Stipitipellis composed of parallel hyphae 2.5–7 μm wide, thin-walled with pale yellowish contents. Caulocystidia 52–88 × 20–34 μm, similar to hymenial cystidia, present throughout the stipe, thick-walled; intermingled with thin-walled paracystidia, these 12–32 × 5–10 μm, in groups at the base of caulocystidia, hyaline. Clamp connections present in all tissues.

Habit and habitat: Scattered on riverbanks in sandy soil under Hopea parviflora.

Additional specimens examined: India, Kerala state, Wayanad District, Muthanga, 15 Aug 2007, TBGT10472; 8 Nov 2007, TBGT10745; 16 Jul 2008, TBGT11405.

Discussion: Inocybe alboviscida Horak (Horak 1979), originally described from Papua New Guinea with Anisoptera (Dipterocarpaceae) and Intsia (Fabaceae) plant associates, most closely matches the Indian materials described here in many macro- and microscopic features. However, the Indian species is distinguished from I. alboviscida by its larger spores with a broadly ellipsoid to ellipsoid outline and different plant associates in low-elevation tropical habitats. Inocybe conicoalba E. Horak (Horak 1980) is similar to I. albonitens as well but differs markedly by its conic to obtuse papillate pileus, presence of persistent veil remnants on the stipe, and smooth amygdaliform to sublimoniform spores. Inocybe olivaceonigra f. volvata (E. Horak) Garrido appears similar to I. albonitens but differs principally by the dry pileus with an olive-black disc, smaller spores(8.0–9.5 × 5.5–6.5 μm), and association with Castanopsis in Papua New Guinea. The non-volvate form of I. olivaceonigra has recently been reported from Castanopsis forests in Yunnan Province, China (Fan and Bau 2013). Other than an obvious alliance with the Inocybe clade, LSU and ITS BLASTn results are equivocal with respect to phylogenetic affinities and reveal no close matches >98 % and >90 %, respectively (the latter with low query coverage). Inocybe wayanadensis K.P.D. Latha & Manim. (Latha and Manimohan 2015) though closely related, differs by its small basidiomata with rimulose pileus, marginate, bulbous stipe and pileipellis an ixotrichoderm. GenBank details are unavailable for this species for molecular comparison.

Inocybe flavosquamulosa C.K. Pradeep & Matheny, sp. nov. Figs. 11 and 17a

MycoBank: MB 813819

Diagnosis: Differs from the Inocybe viscata by its smaller basidiomes, dry pileus with yellowish scales around the umbo, smaller spores, and epicutis of non-gelatinized hyphae. Phylogenetic placement: Inocybe clade (Inocybe viscata group).

Holotype: India, Kerala State, Wayanad District, Ponkuzhy, 8 Nov 2007, TENN070312 (GenBank accession no. KT329450-ITS, KT329456-nLSU); isotype TBGT10743.

Etymology: flavus (yellow), squamulosus (minutely scaly)

Pileus 17–30 mm wide, convex to plano-convex with a broad obtuse umbo; brown to light brown (6E5, 6D4) and pompeian yellow (5C6, 5B4, 5C4, 5D4–5,) elsewhere; surface dry, smooth at the disc, with concolorous (pompeian yellow) appressed to recurved squamules around the umbo, fibrillose-rimose elsewhere; margin straight, entire. Lamellae adnexed, snuff brown (5D5, 6B2, 6C3, 6F4), up to 4 mm deep, crowded with lamellulae of different lengths; edges concolourous with the faces, entire. Stipe 20–45 × 3–5 mm, central, cylindric, curved, narrowly tapering up from a broad base or marginate bulb (this sometimes absent); clay to light brown (5C3, 5D4–5, 6D4); surface fibrillose-striate, entirely pruinose, veil absent. Context stuffed, white, soft. Odor mild to spermatic.

Basidiospores 6.5–8(–9.6) × 4.5–5.5 um, avL = 6.9, avW = 5, Q = 1.14–1.66, avQ. = 1.39, yellowish brown with brown wall (in KOH) with low nodules (knobs not prominent). Basidia 24–29 × 7–8 um, clavate, 4-spored, hyaline or with yellowish brown contents. Lamella edge heteromorphous with metuloidal cystidia and thin-walled paracystidia. Paracystidia difficult to revive in dried specimens, 13–29 × 7–11 μm, clavate, thin-walled, hyaline. Pleurocystidia 31–69 × 13–21 μm, fusoid-ventricose, thick-walled, with apical crystals, abundant. Hymenophoral trama regular, hyphae 8–19 μm wide, thin-walled, hyaline. Subhymenium pseudoparenchymatous. Pileal trama of interwoven hyphae, these 8–17 μm wide, inflated, thin-walled, hyaline. Pileipellis an epicutis of radially arranged hyphae, these 6–10 μm wide, incrusted with yellowish brown contents. Stipitipellis a cutis of parallel incrusted hyphae 3–6 μm wide, hyaline. Caulocystidia 39–89 × 9–17 μm, narrowly lageniform, cylindrical with a broad base, yellowish brown, with apical crystalline deposits, in tufts, more frequent in the upper part; cauloparacystidia 9–26 × 4–13 μm, clavate, cylindro-clavate, thin walled, hyaline. Clamp connections abundant.

Habit and habitat: Solitary, scattered or in groups on riverine sandy soil under Hopea parviflora (Dipterocarpaceae).

Additional Specimens examined: India, Kerala State, Wayanad District, Ponkuzhy, 15 Aug 2007, TBGT10469; 12 Aug 2008, TBGT11686; 16 Aug 2008, TBGT 11404; 24 Sep 2008, TBGT12000.

Discussion: Inocybe flavosquamulosa is a new species in the Inocybe viscata (E. Horak) Garrido group (Matheny and Bougher 2015). Based on BLASTn searches of ITS and nLSU sequences, the new Indian species is most closely related to I. viscata (E. Horak) Garrido (Horak 1977, Matheny and Bougher 2015) and I. torresiae Matheny, Bougher & M.D. Barrett (Bougher et al. 2012). Indeed, our phylogenetic analysis (Fig. 12) supports a close evolutionary relationship between I. flavosquamulosa and I. torresiae from Queensland and northern Western Australia. Inocybe viscata is distinguished by its moderately large basidiomes with a lubricous pileus, large spores, and strongly gelatinized pileipellis. Inocybe torresiae is characterized by its gibbous pentagonal to subtrapeziform spores with 7–10 small obtusely and sharply conical nodules and strong sweet citrine-like odor. This latter species is common at tropical and warm temperate latitudes in northern Australia (Matheny and Bougher 2015). Several other species in the I. viscata group are undescribed or undetermined (Matheny and Bougher 2015), but, aside from I. viscata, all occur in tropical regions (Costa Rica, Papua New Guinea, southeast Asia).

Inocybe purpureoflavida K.B. Vrinda & C.K. Pradeep, Mycotaxon 64: 3 (1997). Figures 13 and 17i

Habit and habitat: Solitary, scattered on riverine sandy soil under Hopea parviflora (Dipterocarpaceae).

Specimens examined: India, Kerala State, Trivandrum District, Palode, TBGRI campus, 15 Apr 1996, TBGT2851; ibid., 12 Jul 1996, TBGT3388 (holotype), TENN070313 (isotype) (GenBank accession no. KT329451-ITS, KT329457-nLSU, KT329445-rpb2).

Discussion: For a complete description of this species, see Vrinda et al. (1997a, b). Inocybe purpureoflavida is remarkable due to the dark purple glutinous pileus, yellowish white stipe with a purple marginate base, odor of radish, large subglobose to ellipsoid spores with 9–12 prominent nodules, presence of thick-walled metuloidal hymenial cystidia and caulocystidia, and association with Dipterocarpaceae. BLASTn results of the ITS sequence suggest I. purpureoflavida may be distributed in Malaysia as well. The nearest ITS match to the type is a mislabeled “Russula sp.” sampled from a basidiome in Malaysia (KP071103) with high (97 %) sequence similarity. BLASTn results of nLSU suggest an alliance with Inocybe viscata (E. Horak) Garriod and related species. Figure 12 illustrates their phylogenetic relationships. This group is characterized by the presence of numerous tropical lineages sampled from Costa Rica, Thailand, Australia, and Papua New Guinea, many of these undescribed or unclarified. BLASTn results of rpb2 are inconclusive (90 % similar to many other nodulose-spored species of Inocybe), however, rpb2 sequences of I. viscata are lacking. Inocybe viscata shares the presence of a glutinous pileus with I. purpureoflavida, nodulose basidiospores, and presence of caulocystidia at least to the center of the stipe.

Inocybe virosa K.B Vrinda, C.K. Pradeep, A.V. Joseph & T.K. Abraham ex C.K. Pradeep, KB Vrinda & Matheny, sp. nov. Figs. 14 and 17h

MycoBank: MB 813820

Inocybe virosa K.B. Vrinda, C.K. Pradeep, A.V. Joseph & T.K. Abraham, Mycotaxon 57: 171. 1996 (invald. Art. 40.7, Melbourne code).

Diagnosis: Differs from species in the Inosperma clade by the combination of the rimose pileus, fibrillose striate stipe, context that does not change color upon exposure, absence of any distinctive odor, small ellipsoid spores, Old World tropical distribution, and presence of muscarine. Differs from the Indian Inocybe carnosibulbosa (described above) by the smaller size of the basidiomes and the non-bulbous stipe base. Unique evolutionary lineage in the Inosperma clade: “Old World tropical clade 2” of Kropp et al. (2013).

Holotype: India, Kerala State, Trivandrum District, TBGRI campus, 18 Jul 1994, Vrinda1098 [28908K (M)].

Habit and habitat: Solitary, scattered or in groups on forest floor or on sandy riverine soil under Myristica, Knema attenuata (Myristicaceae), Vateria indica, Hopea parviflora (Dipterocarpaceae), and Aporusa acuminata (Phyllanthaceae) trees.

Specimens examined: India, Kerala State, Trivandrum District, Palode, TBGRI campus, 16 Oct 1993, TBGT18; 19 Oct1993, TBGT34; 21 Oct 1993 TBGT74; 24 Nov 1993, TBGT431; 26 Nov1993, TBGT441; 22 Apr 1994, TBGT642; 25 May 1994, TBGT753 (TENN070314) (GenBank accession no. KT329452-ITS, KT329458-nLSU, KT329446-rpb2); Palakkadu District, Silent Valley National Park, 18 May1994, TBGT718; 14 Jun 1994, TBGT911; 28 Jul 1994 TBGT1994; Trivandrum District, Agasthyamala, 26 Jul 1994, TBGT1258; Trivandrum District, Kallar, 17 Jun 1994, TBGT884.

Discussion: For a complete description and illustrations, see Vrinda et al. (1996). Inocybe virosa is a now confirmed member of the Inosperma clade of Matheny (2009) where it shares its closest alliance with species in “Old World tropical clade 2” of Kropp et al. (2013) based on BLASTn results of ITS, nLSU, and rpb2 gene sequences, as well as phylogenetic analysis (Fig. 15). The species does not share features in common with many species of the Maculata clade, a major subgrouping within the Inosperma clade, nor with sect. Cervicolores, the other major subgrouping in the Inosperma clade according to Larsson et al. (2009). Many species of the Maculata clade exhibit phaseoliform spores, thin-walled, often clavate to pyriform cheilocystidia, context that changes color upon exposure, a smooth stipe (some with a distinctly bulbous base), and distinctive non-spermatic odors (Larsson et al. 2009). Many of these traits are shared with species of sect. Cervicolores, although many of the European species of the latter tend to have a fibrillose to scaly stipe and/or scaly pileus and lack muscarine (Kuyper 1986). Inocybe virosa differs from these subgroupings by the combination of its longitudinally fibrillose striate stipe lacking a bulbous base, rimose pileus, non-changing context, apparent absence of any distinctive odor, and elliptic spores. The presence of what is likely muscarine (Vrinda et al. 1996) distinguishes this species from sect. Cervicolores, and some species of the Maculata clade as well, which lack muscarine. Thorough morphological notes are lacking for other taxa in “Old World tropical clade 2”, thus documentation and validation of I. virosa are critical to understand species in this novel group. The species is fairly close related to I. carnosibulbosa described above, together with other species from India, Thailand, and Papua New Guinea. Inocybe virosa differs from I. carnosibulbosa by the smaller size of the basidiomes and the non-bulbous stipe base (Figs. 16 and 17).

The name Inocybe virosa was not validly published due to failure to cite the herbarium in which the holotype was deposited (see Art. 40.7, Melbourne code). The herbarium holding the holotype collection is cited here, together with a diagnosis, thus validating the name.

Notes on extralimital taxa

Inocybe mucidiolens (Grund & D.E. Stuntz) Matheny, comb. nov. et stat.nov.

MycoBank: MB 814358

Basionym: Inocybe calamistrata var. mucidiolens Grund & D.E. Stuntz, Mycologia 62(5): 929 (1970).

Discussion: As Fig. 15 demonstrates, this variety of I. calamistrata (Fr.: Fr.) Gillet (sequences analyzed and produced from the isotype) does not cluster with any Fennoscandian sequences of I. calamistrata. Thus, the new combination at the species rank is made. Inocybe mucidiolens is characterized by its green corn odor, dingy yellowish umber pileus, and occurrence under conifers in Washington and Nova Scotia (Grund and Stuntz 1970).