A multivariate morphometric delimitation of species boundaries in the South American genus Nicoraepoa (Poaceae: Pooideae: Poeae)

Abstract

A multivariate morphometric study of the genus Nicoraepoa was carried out to examine patterns of morphological variation among the species and to identify additional characters to allow a clearer delimitation among species. Nicoraepoa is a taxonomically complex genus comprising seven species endemic to South America. Although most of the species are well delimited, two of them, N. andina and N. chonotica, are morphologically similar and very difficult to separate. The morphological variation among species, with overlapping morphological characters, pseudovivipary and possible hybridization make species boundaries unclear. In the present paper, sixty-seven characters were scored for a total of 216 specimens and analyzed using ordination, cluster and discriminant analyses. Based on multivariate results, we recognized species groups and morphological diagnostic characters that allow clearer species delimitation. As a result, N. chonotica has been transferred to N. andina as a subspecies that inhabit southern Patagonia. Other taxa could be recognized and delimited by diagnostic characters: N. erinacea, N. pugionifolia, N. stepparia, N. subenervis subsp. spegazziniana and N. subenervis subsp. subenervis. Moreover, we discuss the possibility that a new species from Bolivia, based on only one specimen, closely related to N. subenervis should be ascribed in Nicoraepoa.

Introduction

Nicoraepoa Soreng & L.J.Gillespie (Poaceae, Pooideae, Poeae) is a South American genus of seven species and two subspecies, thought to be restricted to the Patagonia of Chile and Argentina (Soreng and Gillespie 2007; Soreng and Giussani 2012). Its species were mostly originally described in the large genus Poa L.

Nicora (1978) revised the taxonomy of all the species in Flora Patagonica, accepting them all in Poa subg. Andinae Nicora, except P. subenervis (for authors of the species and subspecies names see Table 1), which she placed in subg. Poa. Soreng and Gillespie (2007) when erecting Nicoraepoa, followed Nicora’s species taxonomy with only few exceptions: Poa borchersii and its synonyms were included in N. chonotica (being Poa chonotica an older name with a Chilean type that Nicora had not accounted for); the two varieties of P. subenervis were raised to subspecies. Poa stepparia, which was included by Nicora (1978) in Poa subg. Andinae, was later transferred to Nicoraepoa by Giussani et al. (2011) after the reassessment of its morphology. Currently, Nicoraepoa includes N. andina, N. chonotica, N. erinacea, N. pugionifolia, N. robusta, and N. stepparia (all gynodioecious and formerly included in Poa subg. Andinae) (Nicora 1977, 1978), and N. subenervis and its two subspecies (which have perfect flowers). Names, synonyms, geographic distribution and habitat of these taxa are summarized in Table 1 and Figs. 1 and 2.

Table 1 Names, synonyms, geographic distribution and habitat description of the known taxa of genus Nicoraepoa

Fig. 1

(Photographs by Liliana M. Giussani)

Nicoraepoa andina. a–b Nicoraepoa andina subsp. andina. Pistillate plants from Copahue, Dept. Ñorquín, Prov. Neuquén, Argentina (Giussani 185). c–d Nicoraepoa andina susbp. chonotica. Perfect plants from Puerto Frías, Dept. Bariloche, Prov. Río Negro, Argentina (Giussani 188b).

Fig. 2

(a photograph by Liliana M. Giussani. b–e photographs by Robert J. Soreng)

Nicoraepoa pugionifolia, N. robusta, and N. subenervis. a–b Nicoraepoa pugionifolia. a From Estancia Cóndor, Güer Aike sección Frayle, Prov. Santa Cruz, Argentina (Giussani 140). b From Sierra de los Baguales, Región de Magallanes y Antártica Chilena, Chile (R.J. Soreng and N.L. Soreng 7336). c Nicoraepoa robusta from Cabo San Isidro, Straights of Magellan, Península de Brunswick, Prov. Magallanes, Chile (Soreng and Soreng 7358 pseudoviviparous & 7359 normal-flowered). d Nicoraepoa subenervis subsp. spegazziniana from ca 5 km above Embalse del Yeso, Valle del Río Yeso, Región Metropolitana, Chile (R.J. Soreng and N.L. Soreng 7155). e Nicoraepoa subenervis subsp. subenervis from Rio Ghio, Ruta 41, Prov. Santa Cruz, Argentina (Peterson et al. 17255).

The phylogenetic independence of Nicoraepoa from Poa was demonstrated by several DNA studies. The first study including some of these seven species (Gillespie and Soreng 2005) used restriction site data of plastid DNA (trnT-trnF, trnF-trnV, trnV-rbcL, rbcL-ORF106, trnH-trnK) and showed that the inclusion of Poa subg. Andinae within Poa made Poa non-monophyletic. Based on these DNA results and morphological differences with Poa, Soreng and Gillespie (2007) proposed that species of subg. Andinae and Poa subenervis should be separated from Poa and treated as the new genus, Nicoraepoa. Later, studies based on sequences of ITS nuclear ribosomal (nr) DNA and plastid trnT-trnL-trn-F (Gillespie et al. 2008) showed Nicoraepoa to be isolated from Poa and evidently allied to the Arctic and sub-Arctic monotypic genus Arctagrostis Griseb. and to the small Australian genus Hookerochloa E.B.Aleexev. Gillespie et al. (2009) and Soreng et al. (2015a) included broader taxon sampling (and in the latter paper more plastid regions, and ETS nrDNA sequences) of genera close to Nicoraepoa, and across subtribe Poinae s.l. (Soreng et al. 2015b). Gillespie et al. (2010) additionally demonstrated that N. pugionifolia has a reticulate history with Poa sect. Parodiochloa (C.E.Hubb.) Soreng. This species probably gained its nrDNA ITS genotype from hybridization with P. flabellata (Lam.) Raspail (the only species of P. sect. Parodiochloa that occurs in South America), while retaining a plastid type and morphology allying it to Nicoraepoa.

Nicoraepoa andina and N. chonotica are closely related species from central-southern Chile and Argentina that are frequently difficult to separate; N. andina grows mainly in highlands in south of Biobío Region, Chile and in the Neuquén Province, Argentina, whereas N. chonotica grows mainly south of Los Ríos Region, Chile and Río Negro Province, Argentina. However, these species overlap in part of their distribution and morphology. Discrimination between N. andina and N. chonotica is further complicated by pseudoviviparous flowering, wherein few if any normally shaped spikelets are produced, and key diagnostic spikelet traits are then mostly lacking for the species. Plants reproducing by pseudoviviparous offshoots are common in southern areas in the distribution of N. chonotica and N. robusta. According to Nicora (1978), the presence of a subapical awn or mucro and the glumes larger than the adjacent lemmas characterize N. andina whereas N. chonotica (as Poa borchersii) has muticous lemmas and the glumes are typically shorter than the adjacent lemmas. Due to the wide variability in these characters and the presence of intermediate specimens, Nicora (1978) suggested that they might represent one single highly variable species. Although the presence or absence of the awn seems to be the most reliable character to distinguish N. andina from N. chonotica, some specimens identified as N. chonotica have spikelets with and without awns in the same inflorescence. Conversely, some one-flowered specimens with glumes longer than the floret and contracted panicles characteristic of N. andina have lemmas without awns. Moreover, some specimens bear two types of spikelets in the same inflorescence.

Thus far, Nicoraepoa was only known from Patagonia of Chile and Argentina (Nicora 1978; Zuloaga et al. 2008; Finot et al. 2011; Giussani et al. 2011; Soreng and Giussani 2012). However, a single specimen collected in northern Bolivia was discovered in the LPB herbarium in 2007 by RJS, which appeared to belong to Nicoraepoa, but it was not clear to which species it might belong or be related to. Thus, we concluded that a thorough morphological numerical study would be useful to address the various species problems.

This paper aims to examine patterns of morphological variation in Nicoraepoa, to search for characters that allow a clearer delimitation between N. andina and N. chonotica, to place the odd Bolivian specimen, and to characterize the pseudoviviparous plants, to analyze the morphological similarity among taxa and to better circumscribe species of Nicoraepoa using multivariate analysis, distribution patterns and study of the types.

Materials and methods

Specimens

Herbarium specimens were studied and borrowed from BAA, CONC, LPB, SGO, SI and US (herbarium acronyms follow Thiers continuously updated). High-resolution images of the types of all species were also examined. For the morphometric study, 216 specimens were selected and considered as operational taxonomic units (OTUs) (Online resource 1). Type specimens were measured from the images, but measurements were not included in the data matrix for morphometric analysis. Specimens were a priori assigned to species according to the taxonomic literature (Nicora 1978; Soreng and Giussani 2012). The number of specimens available varied widely among species: N. erinacea (2 specimens), N. stepparia (2), N. pugionifolia (9), N. subenervis subsp. spegazziniana (12), N. subenervis subsp. subenervis (10), N. robusta (26), N. chonotica (67) and N. andina (87). Additionally, a putative new species of Nicoraepoa represented by only one specimen collected in Bolivia (Valenzuela 1061) was studied; specimens that bear only pseudoviviparous spikelets were excluded from the analyses, but pseudoviviparous plants were included in the analyses when bearing normal spikelets. The specimens included in this study were selected to cover as much as possible the geographic range of distribution and the morphological variability of each species.

Characters scored

Sixty-seven characters (40 quantitative (QN) and 27 qualitative (QL)) (Table 2) were scored for each specimen, from digital photographs taken with a Zeiss STEMI SV8 stereomicroscope equipped with an Axiovision digital camera. Measures from digital images were acquired with the software Zeiss Zen 2011. Measurements correspond to the mean value among 3–4 measurements per character, according to the material availability. Published descriptions and keys (Nicora 1978; Soreng and Peterson 2008; Soreng and Giussani 2012) were consulted to include characters that had previously been considered of taxonomic value. A basic data matrix (BDM) was constructed for 216 specimens (OTUS) and 67 characters.

Table 2 Acronyms, description and character states of the characters included in the multivariate analyses of Nicoraepoa

Handmade leaf sections were cut from the middle zone of a leaf from a sterile innovation. Leaves were rehydrated with detergent solution (SDS) in a water bath for 1 h at 90 °C. Sections were stained with methylene blue and mounted in glycerin jelly. Observations were made with a Zeiss Axiostar microscope, and measurements were made from digital images as previously described. For anatomical terminology, we followed Metcalfe (1960) and Ellis (1976).

Statistical analyses

Qualitative (QL) two-state characters (absence/presence) were coded as 0 = absent, 1 = present; qualitative multistate characters were coded as 1, 2, 3, for different states (Table 2). Normality of the quantitative (QN) variables was determined applying the test of Shapiro and Wilk’s (Mahibbur and Govindarajulu 1997). Quantitative data that do not fit normal distribution were log₁₀-transformed, and those log₁₀-transformed variables that do not fit normal distribution were deleted from the analyses. Data were standardized subtracting from each observation the mean of the column and dividing by the standard deviation. Different methods of analysis were selected to examine the taxonomic structure of Nicoraepoa: cluster analysis (CA), principal coordinate analysis (PCoA) and discriminant analysis (DA). Principal coordinate analysis was chosen to include both QL and QN variables (Gower 1966); PCoA is a good method to represent distances among major groups; a drawback of this method is that it fails to represent distances among members of a group; these are represented more accurately by cluster analysis (Sassone et al. 2013). Cluster analysis was performed using UPGMA algorithm, a robust analysis which tends to join clusters with small variances (Everitt et al. 2011). PcoA and CA were performed using Gower’s dissimilarity, which is a measure of choice when the data matrix contains both continuous and binary data (Gower 1971; Gower and Legendre 1986; Everitt et al. 2011). Minimum spanning trees (MST) were superimposed on the distribution of the OTUs in two-dimensional ordinations. MSTs are important to check if the close position of two objects is an artifact or not (Marhold 2011). The analyses were made in two steps: (1) A matrix including all species (initial dataset with 216 OTUs) was analyzed by PcoA and UPGMA; (2) A reduced matrix including 154 specimens was analyzed by nonparametric classificatory discriminant analysis (DA) using 34 variables, k-nearest neighbor method and Gower distance, to discriminate between N. andina and N. chonotica. Multivariate analyses were carried out using the software Infostat v. 2016p (Di Rienzo et al. 2016). The basic data matrix (BDM) was prepared in Microsoft^® Excel^® 2011 for Mac v. 14.7.0 and is available on request.

Results

Morphometric analysis of the initial dataset

After testing normality of log₁₀-transformed characters, a total of 20 characters were excluded from the analyses. Then, principal coordinate analysis (PCoA) and cluster analysis (UPGMA) were performed on a data matrix including 216 OTUs and 47 characters (27 QL and 20 QN variables) with normal distribution (Table 2). Gower’s distance coefficient was employed, and a minimum spanning tree was superimposed on the distribution of the OTUs on the two principal coordinates. Both PCoA (Fig. 3) and cluster analysis (Online resource 2) yielded similar groupings. Groups correspond to the species as previously classified, except those determined as N. andina and N. chonotica. Only one specimen (Aravena et al. 1108) from Puerto Natales, Magallanes, Chile (r3v) was placed in an intermediate position between N. andina + chonotica and N. robusta. As expected, N. robusta and N. pugionifolia were placed closely although both species form discrete clusters. Nicoraepoa andina and N. chonotica overlap widely along the second axis (Fig. 3) and third axis (not shown). UPGMA phenogram performed with Gower’s distance shows three main clusters: (1) N. andina + N. chonotica, (2) N. pugionifolia + N. erinacea + N. robusta + N. stepparia and (3) Nicoraepoa sp. + N. subenervis. Nicoraepoa robusta and N. pugionifolia form discrete subgroups in the same cluster, with N. erinacea close to N. pugionifolia and N. stepparia close to N. robusta. Nicoraepoa andina and N. chonotica tend to form independent clusters, but N. andina included 18 OTUs identified as N. chonotica whereas N. chonotica included 23 OTUs identified as N. andina (Online resource 2).

Fig. 3

Principal coordinate analysis of the initial dataset, based on 47 characters and 216 OTUs plotted on the first two principal coordinates. A minimum spanning tree was superimposed to the distribution of OTUs. Black diamonds = Nicoraepoa andina; dark blue diamonds = Nicoraepoa sp. (Valenzuela 1061); dark yellow diamonds = N. subenervis subsp. spegazziniana; light yellow diamonds = N. subenervis subsp. subenervis; light green diamonds = N. pugionifolia; gray diamonds = N. erinacea; orange diamonds = N. robusta; red diamonds = N. chonotica; dark green diamonds = N. stepparia

UPGMA performed using only binary (presence/absence) characters (phenogram not shown) showed that differences between N. andina and N. chonotica are mainly supported by the presence or absence of the awn; however, 37 specimens were missplaced.

Discriminant analysis of two taxa: Nicoraepoa andina (long-glumed group) and N. chonotica (short-glumed group)

In order to find out if the separation of N. andina and N. chonotica is feasible, and to identify the characters that best differentiate these taxa, a discriminant analysis was carried out. Specimens were assigned to a priori groups based on the length of the upper glume relative to the length of the adjacent lemmas (G2LEMLR): group 1, glumes longer than adjacent lemmas and group 2, glumes shorter than adjacent lemmas. This character was chosen because N. andina was characterized as having glumes longer than the adjacent lemmas and the presence of a subapical awn or mucro and N. chonotica as having glumes shorter than adjacent lemmas and lemmas without awn or mucro (Nicora 1978). Thus, this character represents the “andina” group (long-glumed group) including all specimens with glumes 1–1.5 times larger than the adjacent lemmas and the “chonotica” group (short-glumed group) including the specimens with glumes shorter (< 1) than the adjacent lemmas. The presence/absence of the awn was not useful to construct groups because of the intraspecific variability of this character. Although the presence or absence of the awn has been considered one of the most reliable characters to distinguish N. andina from N. chonotica, some specimens identified as N. chonotica have spikelets with and without awns in the same panicle. The histogram of the classificatory discriminant analysis (Fig. 4) shows partial separation of both groups. Characters of the spikelet were the most correlated with the canonical axis: Length of the palea (PALEAL), length of the spikelet (SPKL), length of the palea relative to the length of the lemma (PALEALEMLR) and width of the first glume (G1W). The cross-classification table showed 10.39% of the specimens were incorrectly classified (Table 3).

Fig. 4

Discriminant analysis of the Nicoraepoa andina/chonotica complex based on 34 morphological characters and two a priori groups based on the length of the glumes relative to adjacent lemmas

Fig. 5

Map showing the distribution of Nicoraepoa andina subsp. andina and N. andina subsp. chonotica in South America. Blue triangles = N. andina subsp. andina; red circles = pseudoviviparous N. andina subsp. chonotica; yellow circles = normal-flowered N. andina subsp. chonotica

Table 3 Classification table from the classificatory discriminant analysis using six uncorrelated significant variables

Discussion

Based on the results of the morphological multivariate analyses performed and based on the geographic distribution patterns, support was found for recognizing Nicoraepoa subenervis, N. erinacea, N. pugionifolia, N. stepparia and N. robusta as different species. Recognition of N. andina and N. chonotica as distinct species is only possible based on several quantitative characters that showed statistically significant differences. Specimens in the N. andina/chonotica complex have all vascular bundles with abaxial and adaxial sclerenchymatic girders, lemma with distinct intermediate nerves, callus hairs present and lemmas with the keel scabrous on the lower half.

The results support Nicora’s (1978) hypothesis that N. andina and N. chonotica could be better treated as one species; nevertheless, significant differences support their recognition as two different taxa that should be reasonable treated with infraspecific rank. As previously discussed by Nicora (1978), the presence/absence of the awn is inconsistent to distinguish N. andina from N. chonotica. When discussing this character, Nicora (1978) recognized the existence of specimens whose identification is problematic. In contrast, our results support the length of the glume relative to the adjacent lemmas as a good character to separate these taxa. Nevertheless, the lack of morphological discontinuities impedes the recognition of two separate species. Instead, the morphological continuum separating the taxa divides along elevational and geographic ranges, suggesting these taxa are better treated as two subspecies (see below: N. chonotica is transferred to a subspecies of N. andina).

Discrete (QL) characters are not useful to differentiate both subspecies; however, some QN characters significantly differ between them, such as panicle length, panicle width, length of the first glume relative to lemma length, length of the second glume relative to lemma length, length of the awn, plant height, length of the longest panicle branch, number of spikelets in the longest branch of the panicle, length of the upper sheath, lemma length, lemma width, upper leaf length, upper sheath length and half blade width (see key to species and descriptions).

All multivariate analyses support a close morphological relationship between N. pugionifolia and N. erinacea as Nicora (1978) previously pointed out. Nicoraepoa erinacea is endemic to Argentina (Chubut, 43°34′S, 70°27′W); the studied specimens of N. erinacea were collected at median elevation (830 m). Nicoraepoa pugionifolia grows in Chile (Region of Magallanes and Antártica Chilena) and in Argentina (Provinces of Santa Cruz and Tierra del Fuego), from the sea level to 1200 m (Figs. 2a, 6). Morphological differences between N. erinacea and N. pugionifolia are the presence of short callus hairs (present in N. erinacea, absent in N. pugionifolia), leaf section outline (U-shaped in N. erinacea, V-shaped in N. pugionifolia), adaxial ribs in cross section of leaves (absent in N. erinacea, present in N. pugionifolia), spikelets length (longer in N. pugionifolia), second glume length (longer in N. pugionifolia), lemma length (longer in N. pugionifolia), palea length (longer in N. pugionifolia), panicle width (wider in N. pugionifolia), panicle branch length (longer in N. pugionifolia), basal leaf length (longer in N. pugionifolia) and half-lamina length (longer in N. pugionifolia).

Fig. 6

Map showing the distribution of Nicoraepoa erinacea, N. pugionifolia, N. robusta, N. stepparia, N. subenervis and Nicoraepoa sp. in South America. Black circles = normal-flowered N. robusta; blue triangles = N. stepparia; green circles = N. erinacea; light blue circles = N. subenervis subsp. subenervis; orange circles = N. subenervis subsp. spegazziniana; red squares = N. pugionifolia; yellow circles = pseudoviviparous N. robusta

Although Nicora (1978) indicated a close relationship between N. stepparia and N. pugionifolia, our results showed that N. stepparia is morphologically closer to N. robusta than to N. pugionifolia. Nicoraepoa robusta grows in Chile (Region of Magallanes and Antártica Chilena) and Argentina (Tierra del Fuego), from 50°26′ to 55°58´S and 60°29′ to 74°01′W from the sea level to 139 m (Figs. 2c, 6). Nicoraepoa stepparia is endemic to Argentina (Mendoza, Neuquén, Río Negro, 39°32′–41°07′S, 70°31–70°43′W) at 980–1200 m altitude (Fig. 6). Several anatomical and morphological characters clearly distinguish these two species. Gillespie et al. (2008, 2010) found that phylogenetic analyses based on ITS resolved N. pugionifolia within a clade Poa sect. Parodiochloa and sect. Tzvelevia instead with the rest of the genus Nicoraepoa but TLF-based phylogenies resolved N. pugionifolia with Nicoraepoa. As Gillespie et al. (2008, 2010) pointed out, these results are indicative of hybridization and reticulate evolution between Poa and other related genera (unpublished nuclear and plastid DNA data place N. stepparia in Nicoraepoa; L.J.Gillespie pers. comm.). On the other hand, phylogenetic results of Gillespie et al. (2008) resolved N. robusta as sister to N. chonotica.

Pseudovivipary was observed in austral specimens of both subspecies of Nicorapoa andina, and in N. robusta. Pseudoviviparous spikelets occur frequently in N. andina subsp. chonotica. Pseudovivipary results from genetic or environmental triggers that disrupt timing of signals inducing flower development within initiated inflorescences wherein spikelets switch back to development of leaves, which may become a fixed or facultative mode of reproduction. It is a fairly common reproductive phenomenon in grasses. It occurs in heterogeneous terrestrial environments characterized by short growing periods such as arctic and alpine, and Mediterranean habitats (Cabi et al. 2016). It enables plants to complete their life cycle within a short growing season (Elmqvist and Cox 1996; Moore and Dogett 1976; Pierce et al. 2003; Giussani et al. 2016). Pseudovivipary is common in a few Poa species (P. alopecurus (Gaudich. ex Mirb.) Kunth, P. obvallata Steud.) from the same geographic region and in Nicoraepoa (Moore and Dogett 1976), suggesting it is a useful reproductive strategy in wetter and colder zones of the southern Patagonian region.

Nicoraepoa comprises until now seven species endemic to Chile and Argentina. In order to investigate if the specimen Valenzuela 1061 collected in La Paz, Bolivia, at 4200 m.a.s.l. in the border of Lago Challapata, represents a putative new species of Nicoraepoa, this specimen was included in multivariate analyses except DA (Marhold 2011). This specimen resolved close to N. subenervis or within a cluster including N. pugionifolia and N. erinacea suggesting it can be considered a member of this genus. This specimen shows a leaf anatomy that resembles the diagnosis of Nicoraepoa, especially close to the N. andina/chonotica complex (Fig. 7i). This paper was intended to portray patterns of morphological variation to assist us delineating the taxa. It was not possible to achieve these objectives with only one specimen that was not sharply divergent from all the others. Moreover, as Dayrat (2005) contended “no species name should be created based on fewer than a number of specimens…. and never with a single specimen.” For these reasons, this putative new species of Nicoraepoa is not formally described here. We recommend that population sampling and molecular study be conducted to resolve the status of this specimen within the genus Nicoraepoa.

Fig. 7

Nicoraepoa sp. a Herbarium sheet from LPB (Valenzuela 1061). b Portion of the inflorescence. c Spikelet. d Ligule. e Floret. f Apex of the lemma showing the apical mucro. h Callus and rachilla. i Cross section of the leaf blade. Scale bar a 5 cm; b 3 mm; c, d 2 mm; e–h 1 mm; i 0.3 mm

Taxonomic treatment and additional specimens of Nicoraepoa taxa

Key to species and subspecies of Nicoraepoa

1a. Callus glabrous (rarely with a few hairs to 1 mm long in some spikelets) … 2

1b. Callus hairy (with a crown of hairs around the base of the lemma) … 4

2a. Lemmas unawned, 4.8–5.2 mm long; keel scabrous on the upper half … Nicoraepoa sp. (Valenzuela 1061)

2b. Lemmas awned, 11–12 mm long; keel glabrous on the upper half … 3

3a. Plants 8–23 cm tall; panicle 2.8–5.4 cm long; longest branches of the panicle with 1–3 spikelets; leaf blades 3–7.5 cm long; half-lamina in cross section 1–1.8 mm wide; median vascular bundles without sclerenchyma girders; pseudovivipary absent … N. pugionifolia

3b. Plants 11–93 cm tall; panicle 4.4–25.5 cm long; longest branches of the panicle with 3–29 spikelets; leaf blades 6–27 cm long; half-lamina in cross section 1.45–3.5 mm wide; median vascular bundles with abaxial and adaxial sclerenchyma girders; pseudovivipary common … N. robusta

4a. Plants all perfect; anthers fertile, 2–3 mm long; lemmas awned, awn 0.04–0.7 mm long, keel smooth (N. subenervis) … 5

4b. Plants perfect or pistillate; anthers fertile and 3–4 mm long, or sterile staminodes and 1–3 mm long; lemmas awned or unawned; keels glabrous or ciliate on the lower half, scabrous on the upper half, rarely totally glabrous … 6

5a. Plants 17–58.3 cm tall; panicle somewhat lax, 4–16.5 cm long, 0.6–4.1 cm wide; lower branches of the panicle 2–5.5 cm long, bearing 3–12 spikelets; lower glume 3.3–4.7 mm long; callus hairs 0.6–1.4 mm … N. subenervis subsp. spegazziniana

5b. Plants 13–36.5 cm tall; panicle contracted, 2.4–8.7 cm long, 0.6–1.2 cm wide; lower branches of the panicle 1.3–3.2 cm long, with 2–6 spikelets; lower glumes 4.0–5.6 mm long; callus hairs 0.45–1 mm … N. subenervis subsp. subenervis

6a. Lemmas unawned; median vascular bundles free or with adaxial girders only (abaxial girders absent) … 7

6b. Lemmas awned or unawned; leaf blades with median vascular bundles with adaxial and abaxial girders (N. andina) … 8

7a. Plants 7.6–10.5 cm tall; panicle 3.23–3.40 cm long; leaf blades 2.5 cm long; lower glume 4.99–5.52 mm long … N. erinacea

7b. Plants 63–70 cm tall; panicle 8.5–12 cm long; leaf blades 6–7 cm long; lower glumes 4.4–5 mm long … N. stepparia

8a. Glumes shorter than adjacent lemmas; awn usually absent, if present less than 1 mm long; plants (14–) 44–127(–148) cm tall; pseudovivipary common … N. andina subsp. chonotica

8b. Glumes longer than adjacent lemmas; awn up to 2.9 mm, rarely absent; plants (13–)19–84 (–121) cm tall; pseudovivipary rare … N. andina subsp. andina

Nicoraepoa andina (Trin.) Soreng & L.J.Gillespie subsp. andina, Ann. Missouri Bot. Gard. 94(4): 843, f. 4A–G. 2007. ≡ Poa andina Trin., Linnaea 10(3): 306. 1836.—TYPE: Chile austr. in alp. frigidi. mont. ingiv. Antuco, E. Poeppig s.n. (holotype: LE-TRIN 2578.01a [n.v.]; isotypes: BAA fragm. ex LE-TRIN-2578a!, BAA-2449!, BAA-2450!) (Figs. 1a–b, 5).

= Deschampsia latifolia Phil., Linnaea 29(1): 91. 1858, nom. illeg. hom.—TYPE: Chile, in Andibus dep. Linares invenit orn. Germain (holotype: SGO-PHIL 197 [n.v.], isotypes: BAA 885 ex SGO- PHIL 197!, US 556494 ex SGO-PHIL 197!, W [n.v.]).

= Poa straminea Steud., Berberid. Amer. Austr. 52. 1857, nom. nud.

= Poa achrochaeta Hack., Repert. Spec. Nov. Regni Veg. 10(243–247): 172. 1911.—TYPE: Chile, Vulkan Peteroa (no date), K.F. Reiche comm. (holotype: W-39455 (ex SGO-PHIL-448); isotypes: SGO-PHIL-448, US-1723707 (fragm. ex SGO-PHIL-448 & photo), US-88711 (fragm. ex W)) (collector unknown: “448” in Philippi script on ticket).

= Poa aristata Phil., Anales Univ. Chile 43: 574. 1873.—TYPE: Chile, Volcán de Osorno, 1872, C. Juliet (holotype: SGO-PHIL-439 (now W-39450); isotypes: US-89700 (fragm.ex SGO-phil-439 & photo)).

Description: Perennials with rhizomes; plants 46.7 ± 20.8 (13.0–121.0) cm; leaves moderately rigid or indurate; basal leaves 16.5 ± 7.5 (3.2–44.0) cm long, 0.3 ± 0.2 (0.1–1.0) mm wide; ligules oval or truncate, glabrous or sparsely pubescent; ligules of basal leaves 1.3 ± 0.9 (0.2–4.1) mm long; ligules of upper leaf 2.1 ± 0.8 (0.6–5.3) mm. Panicles 11.1 ± 4.9 (0.9–31.7) cm long, 2.4 ± 1.1 (0.1–7.5) cm wide; longest branches of the panicle 4.3 ± 1.9 (2.1–10.4) cm long, bearing 9.6 ± 4.6 (3.7–25.5) spikelets. Spikelets 6.6 ± 1.1 (4.6–9.5) mm; longest pedicels 4.1 ± 2.5 (1.7–20.0) mm long; pedicels glabrous or scabrous; first glumes 5.2 ± 0.9 (3.4–7.0) mm long, 0.7 ± 0.1 (0.4–1.0) mm wide; second glumes 5.7 ± 0.9 (4.1–8.4) mm long, 0.8 ± 0.1 (0.5–1.1) mm wide; rachilla 1.0 ± 0.3 (0.5–2.7) mm; lemmas 5.3 ± 0.6 (4.2–6.7) mm long, 0.9 ± 0.1 (0.7–1.2) mm wide; lemmas glabrous or scabrous on sides; keel glabrous or ciliate on the lower half, scabrous on the upper half; callus hairs 1.5 ± 0.4 (0.6–2.7) mm long; paleas 4.5 ± 0.6 (2.9–5.9) mm; keels scabrous or ciliate; awn 0.9 ± 0.7 (0.0–2.9) mm long.

Leaf anatomy: Cross section V-shaped or expanded; keel rounded not projecting abaxially or acute projecting abaxially; leaf blade asymmetric; longest half-lamina 2.6 ± 0.7 (1.7–5.4) mm wide; leaf thickness in cross section 0.3 ± 0.1 (0.2–0.3) mm; adaxial ribs present; furrows 0.1 ± 0.03 (0.1–0.2) mm depth; first-order adaxial ribs rounded; median vascular bundles with adaxial and abaxial sclerenchyma girders; first-order vascular bundles with adaxial and abaxial sclerenchyma girders; second-order vascular bundles with adaxial and abaxial sclerenchyma girders; sclerenchyma arranged as a continuous hypodermal layer absent or present; prickles on the abaxial epidermis absent or present; prickles on the adaxial epidermis absent or present.

Distribution area and habitats: Nicoraepoa andina subsp. andina is found from 36°17′S to 42°52′S, in Chile (Regions of Biobío, Araucanía, Los Ríos and Los Lagos Region) and Argentina (Provinces of Neuquén, Río Negro, and Chubut), from 310 to 2200 m a. s. l. (Fig. 6), in “mallines” (e.g., Boelcke and Correa 6037; Boelcke 1834), Nothofagus pumilio (lenga) forests (e.g., Soriano 4171), alpine wet meadows with Gunnera (e.g., Boelcke 6481), rocky riparian meadows, disturbed ground in open Nothofagus pumilio forests (e.g., Soreng and Soreng 7119), alpine steppe, around drying ponds (e.g., Soreng and Soreng 7212), open meadows surrounded by N. antarctica, Escallonia and Ribes, meadows with Carex, Eleocharis and Agrostis (e.g., Peterson et al. 17495).

Note: Nicoraepoa andina subsp. andina usually has 2–3-flowered spikelets; however, 1-flowered spikelets are also found.

Nicoraepoa andina (Trin.) Soreng & L.J.Gillespie subsp. chonotica (Phil.) Finot, Soreng & Giussani, comb. nov. ≡ Poa chonotica Phil., Linnaea 29(1): 97. 1858. ≡ Nicoraepoa chonotica (Phil.) Soreng & L.J.Gillespie, Ann. Missouri Bot. Gard. 94(4): 843. 2007.—TYPE: Chile “in monte Cerro de Chonos ad circa 1290 ped. s.m.,” Fonk s.n. (holotype: SGO-PHIL-410 [n.v.]; isotypes: US-89684, fragm. ex SGO-PHIL-410 & photo!, US-89683 fragm. ex SGO-PHIL-410 & photo!) (Figs. 1c–d, 5).

= Poa latifolia Phil., Linnaea 29(1): 97. 1858, nom. illeg. hom.—TYPE: Chile “in monte Cerro de Chonos ad circa 1290 ped. s.m.,” Fonk s.n. (isotypes: BAA-2613 fragm. ex SGO!, BAA-2612 fragm. ex SGO!, US-88768 fragm. ex SGO-PHIL-414 & photo!).

= Poa robusta Phil., Anales Univ. Chile 43: 574. 1873, nom. illeg. hom.—TYPE: Chile “Esta Poa fue hallada en el volcán de Calbuco” Juliet s.n. (holotype: W [n.v.]; isotypes: US-88733 fragm. ex SGO-PHIL-443 & photo!).

= Poa borchersii Phil., Anales Univ. Chile 94: 172. 1896.—TYPE: Chile “prope thermas chillanenses” Borchers s.n. (holotype: W-39457 ex SGO-PHIL-431 [n.v.]; isotype: BAA-2478!).

= Poa chubutensis Speg., Anales Mus. Nac. Hist. Nat. Buenos Aires 7: 196. 1902.—TYPE: Argentina “hab. in rupestribus collinis prope Teka-choique, Chubut, aest. 1901,” N. Illin s.n. (holotype: LPS [n.v.]; isotypes: BAA 2516!, BAA 2517!, SI [n.v.], US 916986!, US 1503958!).

= Poa berningeri Pilg., Notizbl. Bot. Gart. Berlin-Dahlem 10(97): 761. 1929.—TYPE: Chile, Prov. Llanquihue: volcán Yates, ca. 1200 m a.s l.. “vereinzelt zwischen-Nothofagus-an der Waldgrenze,” Mar 1925, Werdermann 1698 (holotype: B; isotypes BAA 2474 fragm. ex B!; US 89693 fragm. ex B!).

Description: Perennial with rhizomes; plants 81.8 ± 28.1 (14.6–148.0) cm; leaves soft to indurate; basal leaves 22.2 ± 10.4 (1.2–55.0) cm long, 0.3 ± 0.1 (0.1–0.5) mm wide; ligules oval or truncate, glabrous or sparsely pubescent; ligules of basal leaves 1.4 ± 0.9 (0.2–5.5) mm long; ligules of upper leaves 2.4 ± 1.0 (0.5–5.1) mm. Panicles 18.7 ± 4.4 (11.2–28.0) cm long, 5.4 ± 2.7 (1.6–13.5) mm wide; longest branches of the panicles 8.8 ± 3.8 (4.0–21.0) cm long, bearing 5.0–61.0 spikelets. Spikelets 7.0 ± 0.9 (5.0–9.2) mm; longest pedicels 4.6 ± 1.6 (2.0–8.4) mm long; pedicels scabrous or pilose; first glumes 5.4 ± 0.7 (3.9–7.1) mm long, 0.7 ± 0.1 (0.5–1.2) mm wide; second glumes 6.0 ± 0.8 (4.3–8.1) mm long, 0.9 ± 0.1 (0.7–1.3) mm wide; rachilla 1.0 ± 0.3 (0.4–2.0) mm; glabrous or pubescent; lemmas 6.0 ± 0.8 (4.5–8.5) mm long, 1.0 ± 0.1 (0.6–1.4) mm wide; lemmas smooth or scabrous on sides; keel glabrous or ciliate on the lower half, scabrous on the upper half; callus hairs 1.4 ± 0.4 (0.5–2.7) mm long; paleas 4.8 ± 0.5 (3.4–6.1) mm, keels scabrous or ciliate; awn 0.2 ± 0.2 (0.0–1.0) mm long.

Leaf anatomy: Cross section V-shaped or expanded; keel rounded not projecting abaxially or acute projecting abaxially; leaf blade asymmetric; longest half-lamina 3.0 ± 0.6 (2.1–5.0) mm long; leaf thickness in cross section 0.3 ± 0.04 (0.2–0.5) mm; adaxial ribs present; furrows 0.1 ± 0.02 (0.1–0.2) mm depth; first-order adaxial ribs rounded; median vascular bundles with abaxial sclerenchyma girders only or with adaxial and abaxial sclerenchyma girders; first-order vascular bundles with adaxial and abaxial sclerenchyma girders; second-order vascular bundles with abaxial sclerenchyma girders only or with adaxial and abaxial sclerenchyma girders; sclerenchyma arranged as a continuous hypodermal layer absent or present; prickles on the abaxial epidermis absent or present; prickles on the adaxial epidermis absent or present.

Distribution area and habitats: Nicoraepoa andina subsp. chonotica grows from 36°53′S to 54°05′S, in Chile in the Regions of Biobío, Araucanía, Los Ríos, Los Lagos, Aysén and Magallanes and Antártica Chilena and in Argentina in Provinces of Neuquén, Río Negro, Chubut and Santa Cruz (Fig. 6), in marshes with Nothofagus pumilio, N. antarctica, N. dombeyi, Carex sp. and Juncus sp., littoral vegetation, muddy lake foreshore, peat bogs in Fitzroya cupressoides forests (“alerzales”), also in Sphagnum meadows surrounded by Nothofagus betuloides forests (e.g., Soreng and Soreng 7255).

Notes: Type of P. chubutensis in BAA 2516 (ex Herb. Spegazzini 68), collected at río Corcovado, Chubut, by N. Illin in 1901 is a fragment with spikelets 6.3–6.6 mm long; lower glumes 4.8 mm long; upper glumes 5.3 mm; lemmas 4.6–5.3 mm, the apex acute, muticous. Type of P. chubutensis at US 1503958 has open, lax panicles ca. 17.5 xm long. Type of P. berningeri at BAA 2474 has glabrous leaf blades ca. 10 mm wide; 2-flowered spikelets 6.2–7.0 mm long, glumes purple; lower glume 4.5 mm; upper glume 5 mm long, ca. 1 mm wide; lemmas with acute, muticous apex.

Pseudoviviparous material of subsp. chonotica is mostly known from the region of geographic overlap with western populations of N. robusta between 49 and 52°s, where normal-flowered subsp. chonotica is rare, but occurs as far north as 46.6°S. Nicoraepoa robusta is commonly pseudoviviparous from throughout the species range, from 50 to 56°S, over the same range that subsp. chonotica is pseudoviviparous, and well eastward of that as far as Isla de Los Estados, and pseudoviviparous and normal-flowered plants are commonly found together. These taxa are separable by the more lax open inflorescence and frequent occurrence of at least a few callus hairs in spikelets in N. andina subsp. chonotica versus contracted inflorescences and no callus hairs in N. robusta. A few putative hybrids between N. robusta and N. andina subsp. chonotica were identified in herbarium materials, as too intermediate to separate (e.g., Pisano 5954, Fiordo Peel, Río Murtillar, 18 Nov 1985 (CONC), Pisano 6464, Canal Grappler, Paso Charteris, Cabo Colorado, 19 Dec 1988 (CONC)). Pseudovivipary was observed in only one specimen of subsp. andina (Los Lagos, Cerro O’Connor, Rúgolo et al. 12417). Pseudovivipary is rare in the interface between subsp. andina and subsp. chonotica.

Nicoraepoa erinacea (Speg.) Soreng & L.J.Gillespie, Ann. Missouri Bot. Gard. 94(4): 844, f. 5A–D. 2007. ≡ Poa erinacea Speg., Anales Mus. Nac. Hist. Nat. Buenos Aires 7: 198. 1902.—TYPE: Argentina, Chubut “in aridissimis subsalcis secus Rio Chubut, Dec 1899” N. Illin s.n. (holotype: LPS-67 in LP!; isotypes: BAA-2534!, US-88783!, MPU-027785!) (Illustration: Soreng and Giussani 2012, p. 273) (Fig. 6).

Description: Perennial with rhizomes 1–1.5 mm in diameter; plants 9.1 ± 2.0 (7.7–10.5) cm; leaves indurate; basal leaves 2.5 ± 0.02 (2.5–2.55) cm long, 0.3 ± 0.1 (0.2–0.3) mm wide; ligules truncate, glabrous; ligules of basal leaves 1.0 ± 0.4 (0.7–1.3) mm long; ligules of upper leaf 1.3 ± 0.8 (0.7–1.8) mm. Panicles 3.3 ± 0.1 (3.2–3.4) cm long, 0.5 ± 0.2 (0.3–0.6) cm wide; longest branches of the panicle 1.0 ± 0.1 (0.9–1.0) cm long, bearing 1.0 spikelet. Spikelets 6.5 ± 0.6 (6.1–6.9) mm; longest pedicels 5.0 ± 1.8 (3.7–6.3) mm long; pedicels glabrous or scabrous; first glume 5.3 ± 0.4 (5.0–5.5) mm long, 0.8 ± 0.00 mm wide; second glume 5.6 ± 0.8 (5.1–6.1) mm long, 1.0 ± 0.1 (0.9–1.1) mm wide; rachilla 1.2 ± 0.2 (1.1–1.3) mm, glabrous; lemmas 5.9 ± 0.4 (5.6–6.2) mm long, 1.1 ± 0.0 mm wide; lemmas smooth on sides; keel glabrous on the lower and upper halves; callus hairs 0.3 ± 0.0 mm long; paleas 4.6 ± 0.6 (4.1–5.0) mm, keels ciliate; awn absent or reduced to a short mucro 0.1 ± 0.1 (0.0–0.16) mm long.

Leaf anatomy: Cross section U-shaped; keel rounded not projecting abaxially; leaf blade asymmetric; longest half-lamina 0.8 ± 0.1 (0.8–0.9) mm long; leaf thickness in cross section 0.3 ± 0.0 mm; adaxial ribs absent; furrows absent; median vascular bundles free; first-order vascular bundles free; second-order vascular bundles free; sclerenchyma arranged as a continuous hypodermal layer absent; prickles on the abaxial epidermis absent; prickles on the adaxial epidermis present.

Distribution area and habitats: Nicoraepoa erinacea is endemic to Argentina, where it has been collected only in the Province of Chubut (Fig. 7). It forms cespitose cushions on alkaline, saline soils. It is closely related to N. pugionifolia from which it is distinguished by having shorter spikelets, callus with short hairs (callus glabrous in N. pugionifolia), leaves subulate (conduplicate, sometimes flat at the base in N. pugionifolia) and adaxial ribs absent on the leaf section (present in N. pugionifolia).

Note: Type specimen BAA-2534 bears three plants 10–15 cm tall; leaves glabrous, very narrow, 2-3 cm long, ending in a sharp pointed apex; panicles 1.8–3 cm long; spikelets 6 mm long; glumes shorter than the florets. Collected in flower from December to April (Nicora 1978).

Additional specimens examined: ARGENTINA, Prov. Chubut, Quichaura, 5 Apr 1952, A. Soriano 4393 (BAA); Quichaura, near Tecka, 10 km S of Esquel, s.d., A.A. Beetle and A. Soriano 446/52 (BAA).

Nicoraepoa pugionifolia (Speg.) Soreng & L.J.Gillespie, Ann. Missouri Bot. Gard. 94(4): 844, f. 4P–S. 2007. ≡ Poa pugionifolia Speg., Anales Mus. Nac. Hist. Nat. Buenos Aires 7: 199. 1902.—TYPE: Argentina, “in rupestribus porphyricis Parr-aik secus Río Chico et Boron-aik secus Río Sehuen, Jan. et Febr. 1898” Ameghino s.n. (lectotype: LP-SPEG-65! designated by R.J. Soreng & L.J.Gillespie, Ann. Missouri Bot. Gard. 94: 845. 2007; isolectotypes: BAA-2672!) (Figs. 2a–b, 6).

= Poa acutissima Pilg., Repert. Spec. Nov. Regni Veg. 12: 306. 1913.—TYPE: Argentina “Süd-Patagonien, Skottsberg s.n. (holotype: B [n.v.]; isotypes: BAA-2442!, BAA-2443!).

Description: Perennial rhizomatose plants forming cushions up to 1 m in diameter; rhizomes with serial tillers; plants 14.4 ± 4.3 (8.7–23.0) cm; leaves moderately rigid to indurate; basal leaves 4.6 ± 1.3 (3.0–7.5) cm long, 0.3 ± 0.2 (0.2–0.8) mm wide; leaves with the apex ending abruptly in a very sharp point, and wide and bright sheaths; ligules oval or truncate, glabrous; ligules of basal leaves 1.2 ± 0.5 (0.6–1.8) mm long; ligules of upper leaves 1.3 ± 0.3 (0.7–1.8) mm. Panicles 3.9 ± 0.9 (2.8–5.4) cm long, 0.9 ± 0.3 (0.5–1.4) cm wide; longest branches of the panicle 1.5 ± 0.3 (1.2–2.1) cm long, bearing 1–3 spikelets. Spikelets 9.2 ± 1.3 (7.9–11.3) mm; longest pedicels 4.4 ± 0.9 (3.3–5.8) mm long; pedicels glabrous or scabrous; first glume 6.3 ± 0.7 (5.4–7.5) mm long, 1.0 ± 0.2 (0.8–1.2) mm wide; second glume 7.0 ± 0.7 (6.0–8.4) mm long, 1.2 ± 0.2 (0.9–1.5) mm wide; rachilla 1.6 ± 0.4 (1.0–2.4) mm; glabrous or scabrous; lemmas 7.1 ± 0.3 (6.7–7.6) mm long, 1.2 ± 0.2 (0.8–1.4) mm wide; lemmas smooth on sides; keel glabrous or scabrous on the lower half, smooth on the upper half; callus glabrous (rarely with a sparse crown of hairs on a few florets; e.g., Peterson et al. 17128); paleas 5.8 ± 0.4 (5.2–6.4) mm, keels scabrous or ciliate; awn absent, but sometimes with a very short mucro 0.2–0.3 µm long (e.g., Dauber 176, Vallerini 3975).

Leaf anatomy: Cross section V-shaped; keel rounded, not projecting abaxially; leaf blade asymmetric; longest half-lamina 1.4 ± 0.3 (1.0–1.8) mm long; leaf thickness in cross section 0.3 ± 0.04 (0.2–0.3) mm; adaxial ribs present; furrows 0.1 ± 0.0 (0.1–0.2) mm depth; first-order adaxial ribs rounded; median vascular bundles free or with abaxial sclerenchyma girders only; first-order vascular bundles free or with adaxial sclerenchyma girders; second-order vascular bundles free; sclerenchyma arranged as a continuous hypodermal layer absent; prickles on the abaxial epidermis absent or present; prickles on the adaxial epidermis absent or present.

Distribution area and habitats: Nicoraepoa pugionifolia grows in Argentina (Provinces of Santa Cruz and Tierra del Fuego) and Chile (Magallanes and Antártica Chilena Region), from 47°04′S to 53°51′S, from the sea level to 1200 m of elevation (Fig. 7). It grows in dry lowlands (e.g., Dauber 176) and saline inundate meadows (mallines) (e.g., Vallerini 3975, Peterson et al. 17254) with Carex, Calamagrostis and Azorella, between 60 and 1200 m.s.m.

Notes: Some Argentinian specimens collected in Tierra del Fuego (e.g., Vallerini 3975, Castellanos 7554) have very narrow leaves (see also comments made by Nicora 1978). Types BAA 2442 and BAA 2443 of Poa acutissima have spikelets 7.7–9.0 mm long, first glumes 5.8 mm long × 0.8 mm wide, second glumes 7.5 mm long x 1.1 mm wide and lemmas 5 mm long, callus and awn absent; plants are 5.0–7.5 cm tall, with basal leaves 2.0–2.5 cm long x 1.0–1.3 mm wide. These measurements are within the range of variation observed for the species. Collected in flower from November to January.

Nicoraepoa robusta (Steud.) Soreng & L.J.Gillespie, Ann. Missouri Bot. Gard. 94(4): 844-845, f. 5E–I. 2007. ≡ Poa robusta Steud., Syn. Pl. Glumac. 1: 426. 1854.—TYPE: Chile, Magallanes “in paludosis maritimis Sandy Point Magellan” Lechler 1191 (holotype: P!; isotypes: BAA 2776 ex P!, US-946984!, US-81586!) (Figs. 2c, 6).

= Festuca arenaria Lam., Tabl. Encycl. 1: 191. 1791, nom. illeg. hom. ≡ Poa arenicola St.-Ives, Candollea 3: 282. 1927.—TYPE: Chile or Argentina “E. Magellania, in arenis maritimis” Commerson s.n. (holotype: P!; isotypes: US-2875377a fragm. & photo ex MPU!, US-2875377b fragm. Ex P!).

Description: Perennials with thick rhizomes; frequently with pseudoviviparous spikelets; plants 41.8 ± 22.3 (11.5–93.1) cm; leaves indurate; basal leaves 12.4 ± 5.6 (6.0–27.0) cm long, 0.3 ± 0.1 (0.2–0.7) mm wide; ligules oval or truncate, glabrous or pubescent; ligules of basal leaves 1.1 ± 0.5 (0.6–2.8) mm long; ligules of upper leaves 1.9 ± 0.9 (0.7–4.8) mm. Panicles spiciform, 11.1 ± 4.9 (4.4–25.5) cm long, 2.5 ± 2.3 (0.9–11.3) cm wide; longest branches of the panicles 4.4 ± 2.7 (1.7–10.6) cm long, bearing 3–16(–29) spikelets. Spikelets 9.2 ± 1.4 (6.7–12.1) mm; longest pedicels 5.2 ± 1.8 (2.0–10.2) mm long; pedicels scabrous or pilose; first glume 7.2 ± 1.3 (5.3–10.2) mm long, 0.9 ± 0.2 (0.5–1.5) mm wide; second glume 7.6 ± 1.3 (5.3–10.3) mm long, 1.0 ± 0.2 (0.6–1.6) mm wide; rachilla 1.4 ± 0.3 (0.9–2.6) mm, glabrous; lemmas 7.4 ± 0.8 (5.9–9.5) mm long, 1.2 ± 0.2 (0.9–1.6) mm wide; lemmas smooth or scabrous on sides; keel glabrous on the lower half, glabrous or scabrous on the upper half; callus hairs absent, rarely present 0.2 ± 0.4 (1.1–1.4) mm long; paleas 6.2 ± 0.7 (4.8–7.9) mm, keels scabrous or ciliate; awn absent or reduced to a short mucro 0.1 ± 0.2 (0.6–0.8) mm long.

Leaf anatomy: Cross section V-shaped or U-shaped; keel rounded, not projecting abaxially; leaf blade asymmetric; longest half-lamina 2.2 ± 0.5 (1.5–3.5) mm wide; leaf thickness in cross section 0.3 ± 0.1 (0.2–0.4) mm; adaxial ribs present; furrows 0.2 ± 0.1 (0.1–0.3) mm depth; first-order adaxial ribs rounded; median vascular bundles with abaxial sclerenchyma girders only or with adaxial and abaxial sclerenchyma girders; first-order vascular bundles with adaxial and abaxial sclerenchyma girders; second-order vascular bundles with adaxial and abaxial sclerenchyma girders; sclerenchyma arranged as a continuous hypodermal layer absent; prickles on the abaxial epidermis absent; prickles on the adaxial epidermis absent or present.

Distribution area and habitats: Nicoraepoa robusta is found in Argentina (Malvinas Islands, Tierra del Fuego) and Chile (Region of Magallanes and Antártica Chilena), from 50°26′S to 55°58′S, from the sea level to 140 m of altitude (Fig. 7), on coastal scrubs, at the interface of marshy meadows and the rocks and dunes; coastal herbaceous associations with Anthoxanthum redolens (Vahl) P.Royen, Marsippospermum grandiflorum (L.f.) Hook.f., Elymus magellanicus (E.Desv.) Á.Löve. Sometimes attacked by Claviceps sp. (e.g., Domínguez 985, 990).

Notes: Nicora (1978) and Soreng and Giussani (2012) characterize N. robusta as having the callus glabrous. In a few specimens (e.g., Pisano 6464, Aravena et al. 1108), we found callus with hairs 1.07–2.09 mm long, and these are considered possible intermediates between N. robusta and N. andina subsp. chonotica.

The isotype of Poa robusta (BAA 2676) has leaves 8.5–9.0 cm long x ca. 4 mm lat, glabrous, acute; spikelets ca. 7 mm long; first glumes 6 × 1 mm; second glumes 7.2 × 1.5 mm; lemmas 6–7 mm with glabrous calluses. A drawing of the inflorescence of the Paris (P)-type specimen made by L.R. Parodi shows a spiciform panicle ca. 6 cm long, 1 cm lat. These measurements are within the range of variation of the species.

Nicoraepoa stepparia (Nicora) Soreng, Darwiniana 49(1): 91. 2011. ≡ Poa stepparia Nicora, Hickenia 1(18): 101. 1977.—TYPE: Argentina, Neuquén, Dpto. Zapala, Zapala, 5 Feb 1920, L.R. Parodi 1268 (holotype: BAA!) (Illustration: Soreng and Giussani 2012, p. 276) (Fig. 6).

Description: Perennials with rhizomes; plants 66.5 ± 5.0 (63.0–70.0) cm; leaves moderately rigid or indurate, relatively short, conduplicate, with very acute apex, forming a dense clump that does not exceed 10 or 15 cm high; basal leaves 6.5 ± 0.7 (6.0–7.0) cm long, 0.2 ± 0.0 mm wide; ligules truncate, glabrous; ligules of basal leaves 1.0 ± 0.0 mm long; ligules of upper leaves 1.8 ± 0.0 mm. Panicles panicle linear, narrow, 10.3 ± 2.5 (8.5–12.0) cm long, 1.3 ± 0.4 (1.0–1.5) cm wide; longest branches of the panicles 4.9 ± 1.2 (4.0–5.7) cm long, bearing 5 spikelets. Spikelets 6.4 ± 1.3 (5.5–7.3) mm; longest pedicels 6.9 ± 2.1 (5.4–8.3) mm long; pedicels glabrous; first glume 4.7 ± 0.9 (4.4–5.0) mm long, 0.9 ± 0.0 mm wide; second glumes 5.3 ± 0.3 (5.1–5.5) mm long, 1.0 ± 0.0 mm wide; rachilla 1.4 ± 0.0 mm; lemmas 6.4 ± 0.8 (5.9–7.0) mm long, 1.3 ± 0.1 (1.2–1.4) mm wide; lemmas glabrous on sides (but see comments in Nicora 1978, p. 171 and fig. 111); keel glabrous on the lower and on the upper halves; callus hairs 0.4 ± 0.0 mm long; paleas 5.3 ± 0.0 mm; keels scabrous; awn 0.5 ± 0.0 mm long. Caryopsis 2.0–2.5 mm, subtriangular in cross section.

Leaf anatomy: Cross section V-shaped; keel rounded, not projecting abaxially; leaf blade asymmetric in cross section; longest half-lamina 1.6 ± 0.3 (1.4–1.8) mm long; leaf thickness in cross section 0.3 ± 0.1 (0.3–0.4) mm; adaxial ribs present; furrows 0.1 ± 0.0 mm depth; first-order adaxial ribs rounded; median vascular bundles free; first-order vascular bundles with adaxial and abaxial sclerenchyma girders; second-order vascular bundles with adaxial and abaxial sclerenchyma girders; sclerenchyma arranged as a continuous hypodermal layer absent; prickles on the abaxial epidermis absent; prickles on the adaxial epidermis absent.

Distribution area and habitats: Endemic to Argentina (39°32′S – 41°07′S, Mendoza, Neuquén, Río Negro), from 980 to 1200 m (Fig. 7), growing on inundate meadows (mallines) and saltpeter soils.

Notes: Type specimen of Poa stepparia (BAA) has two complete plants with inflorescences; leaves glabrous, 5–7 cm long, with a sharp pointed apex; spikelets 7–9.5 mm; first glumes 5 mm long, 1.2 mm wide; second glumes 5.5 mm long, 1.2 mm wide.

According to Nicora (1978) this species is closely allied to N. pugionifolia. Nicoraepoa stepparia differs from that in having shorter spikelets (5.5–7.3(–8) mm in N. stepparia, 7.9–11(–12) mm in N. pugionifolia), shorter glumes, shorter lemmas, callus with short hairs (callus glabrous in N. pugionifolia), and taller plants (63–70 cm high in N. stepparia, 8.7–23 cm in N. pugionifolia). Collected in flower from September to January.

Nicoraepoa subenervis (Hack.) Soreng & L.J.Gillespie, Ann. Missouri Bot. Gard. 94(4): 845, f. 5 N–J. 2007. ≡ Poa subenervis Hack., Ark. Bot. 7(2): 7, t. 2, f. 2. 1908.—TYPE: Argentina, Santa Cruz “in paludosis inter, Lago Viedma et Laguna Tar, ca. 1000 m, 27 Feb 1905” P. Dusén 6021 (lectotype: W [n.v.], designated by R.J. Soreng and L.J.Gillespie, Ann. Missouri Bot. Gard. 94: 845. 2007; isolectotypes: US-88723!, K!, BAA ex US!) (Figs. 2d–e, 6).

Description: Plants 28.3 ± 11.4 (11.3–58.3) cm; leaves soft or indurate; basal leaves 5.3 ± 3.2 (2.3–13.0) cm long, 0.3 ± 0.1 (0.1–0.5) mm wide; ligules oval or truncate, sparsely pubescent or densely pubescent; ligules of basal leaves 0.7 ± 0.4 (0.2–1.5) mm long; ligules of upper leaves 1.0 ± 0.6 (0.3–3.2) mm. Panicles 6.9 ± 3.1 (2.4–16.5) cm long, 1.2 ± 0.8 (0.6–4.1) cm wide; longest branches of the panicles 2.8 ± 1.0 (1.3–5.5) cm long, bearing 1–12 spikelets. Spikelets 6.0 ± 0.7 (5.1–7.4) mm; longest pedicels 8.6 ± 5.5 (0.8–20.7) mm long; pedicels scabrous or pilose; first glume 4.4 ± 0.5 (3.3–5.6) mm long, 0.8 ± 0.2 (0.5–1.1) mm wide; second glume 4.9 ± 0.6 (3.8–6.0) mm long, 0.9 ± 0.2 (0.6–1.3) mm wide; rachilla 1.1 ± 0.2 (0.4–1.4) mm, glabrous or scabrous; lemmas 4.7 ± 0.5 (3.7–5.8) mm long, 1.0 ± 0.1 (0.7–1.1) mm wide; lemmas smooth or scabrous on sides; keel glabrous on the lower half, scabrous on the upper half; callus hairs 1.0 ± 0.3 (0.5–1.4) mm long; paleas 3.8 ± 0.3 (3.3–4.4) mm, keels scabrous or ciliate; awn 0.3 ± 0.2 (0.0–0.7) mm long.

Leaf anatomy: Cross section V-shaped or expanded; keel rounded not projecting abaxially; leaf blade asymmetric in cross section; longest half-lamina 1.4 ± 0.4 (0.8–2.2) mm long; leaf thickness in cross section 0.2 ± 0.1 (0.2–0.3) mm; adaxial ribs present; furrows 0.1 ± 0.0 mm depth; first-order adaxial ribs rounded; median vascular bundles with adaxial and abaxial sclerenchyma girders; first-order vascular bundles with abaxial sclerenchyma girders only or with adaxial and abaxial sclerenchyma girders; second-order vascular bundles free; sclerenchyma arranged as a continuous hypodermal layer absent; prickles on the abaxial epidermis absent; prickles on the adaxial epidermis absent or present.

Nicoraepoa subenervis subsp. spegazziniana (Nicora) Soreng & L.J.Gillespie, Ann. Missouri Bot. Gard. 94(4): 845.2007. ≡ Poa spegazziniana Parodi, Dansk Bot. Ark. 22(1): 67. 1963, nom. nud. ≡ Poa subenervis Hack. var. spegazziniana Nicora, Hickenia 1(18): 103. 1977.—TYPE: Argentina, Mendoza, Dpto. San Rafael, Valle del Atuel, Arroyo Colorado, T.W. Böcher, J.P.K. Hjerting and K. Rahn 1306 (holotype: BAA-2706-1!; isotype: SI-62364!) (Figures 2d, 7).

Nicoraepoa subenervis subsp. spegazziniana differs from subsp. subenervis having longer and wider panicles (4.0–16.5 cm long, 0.6–4.1 cm wide in subsp. spegazziniana vs. 2.4–8.7 cm long, 0.6 – 1.2 cm wide in subsp. subenervis); plants of subsp. spegazziniana are taller (17.1–58.3 cm) than those of subsp. subenervis (13.3–36.5 cm).

Distribution area and habitats: Nicoraepoa subenervis subsp. spegazziniana grows in Argentina (San Juan, Mendoza and Santa Cruz) and Chile (Metropolitan Region and Region of Libertador Bernardo O´Higgins) (30°22′S–34°05′S) from 2600 to 3320 m a. s. l. of elevation (Fig. 7), on rocky slopes near water (e.g., Peterson et al. 19296), and marshes (e.g., Kurtz 9609).

Note: Types BAA 2706-1 and 2706-2 of Poa subenervis var. spegazziniana include four and one almost complete plants, respectively. Plants are 30–35 cm tall, with basal leaf blades 6.6 cm long, 6.1–6.5 cm long x 1.7–2.9 mm lat; panicles 8–10 cm long x 1.4–2.2 cm lat; spikelets 7.8 mm long, first glume 5–5.2 mm long × 0.9 m wide, second glume 5.2–5.7 mm × 1 mm wide. These measurements are within the range of variation of the subspecies.

Nicoraepoa subenervis subsp. subenervis (Figures 2e, 6).

Distribution area and habitats: Nicoraepoa subenervis subsp. subenervis grows in southern Chile (Magallanes) and southern Argentina (Santa Cruz) (Fig. 7); the citation of subsp. subenervis for Prov. San Juan, Argentina (Soreng and Giussani 2012) is erroneous, based on the specimen P.M. Peterson et al. 19296 that belongs to subsp. spegazziniana. This subspecies grows in wet meadows with Carex, Calamagrostis and Azorella, mesic vegas and rocky slopes along rivers, up to 1200 m. a. s. l.

Nicoraepoa sp. (Valenzuela 1061) (Fig. 7).

Description: Plants perfect, perennials, 20 cm tall, decumbent at the base; leaf sheaths glabrous; basal leaf sheaths 1.0–3.0 cm long; upper leaf sheaths 4.0 cm long; ligule truncate, glabrous on the back, minutely denticulate at the apex; ligule of basal leaves 1.6 mm long; ligule of upper leaves 2.0 mm long; leaf blades glabrous, ending in a sharp pointed apex; basal leaf blades 2.0–3.2 cm long, 1.0–2.0 mm width, glabrous, moderately rigid; upper leaf blade 3.5 cm long. Inflorescence a dense, spiciform panicle, 4.5–4.6 cm long, 0,8–1.0 cm wide; rachis glabrous; longest branches 1.2–1.8 cm. Spikelets 5.7–6.3 mm long, 2–3-flowered, shortly pedicellate, sometimes somewhat purple; pedicels 0.7-2.8 mm long, glabrous; glumes shorter than the florets; first glume 3.3–3.7 mm long, 0.6 mm wide, 1-nerved; second glume 3.8–4.0 mm long, 0.8–1.0 mm wide, 3-nerved; rachilla internodes 1.0–1.1 mm long, glabrous; first lemma 4.8–5.2 mm long, 0.8–1.0 mm wide, glabrous, the keel smooth, the apex hyaline, a short mucro born 0.1 mm below the apex; callus glabrous; upper lemmas shorter; palea 3.2–4.2 mm long; lodicules 0.7–0.9 mm long; anthers 3, 2.5 mm long, fertile; ovary with plumose stigmata. Fruit not seen.

Leaf anatomy: Leaf in cross section V-shaped in outline; half-lamina 1.7 mm long, 0.25 mm thick at the median bundle and 0.19 mm thick at the middle portion; keel rounded, not notably projected abaxially; adaxial ribs present, more or less rounded at the apex; furrows 0.07 mm deep; epidermal cells more or less rounded in cross section; bulliform cells in groups of four or five at the bottom of the furrows; adaxial epidermis with prickles; abaxial epidermis smooth; median, first-order and second-order vascular bundles with adaxial and abaxial girders of sclerenchyma; third-order vascular bundles free; sclerenchyma mostly limited to the margins.

Information on Electronic Supplementary Material

Online resource 1. Additional specimens examined of Nicoraepoa in the herbaria BAA, CONC, LPB, SGO, SI, and US.

Online resource 2. UPGMA phenogram of the initial dataset based on a basic data matrix including 67 qualitative and quantitative characters and 216 OTUs of Nicoraepoa.

Online resource 3. Specimens included in the multivariate analyses of Nicoraepoa (names according to the initial identification).