New combinations and updated descriptions in Podagrostis (Agrostidinae, Poaceae) from the Neotropics and Mexico

Abstract Based on morphological study and corroborated by unpublished molecular phylogenetic analyses, five grass species of high-mountain grasslands in Mexico, Central and South America, Agrostisbacillata, A.exserta, A.liebmannii, A.rosei, and A.trichodes, are transferred to Podagrostis and bring the number of species of this genus recognized in the New World to ten. The name Aperaliebmannii is lectotypified and epitypified. We provide an updated genus description for Podagrostis, and updated species descriptions, images, and notes on the new combinations. The diagnostic characteristics differentiating Podagrostis from Agrostis are: a) palea that reaches from (2/3) ¾ to almost the apex of the lemma; b) florets that usually almost equal the length of the glumes or are at least ¾ the length of the glumes; c) rachilla extension present and emerging from under the base of the palea as a slender short stub (rudimentary or up to 1.4 mm long, sometimes obscure in most florets in P.rosei), smooth or scaberulous, glabrous or distally pilulose (hairs < 0.3 mm long); d) lemmas usually awnless, sometimes with a short straight awn 0.2–0.6 mm long, inserted medially or in the upper 1/3 of the lemma, not surpassing the glumes (awn well-developed, straight or geniculate and inserted in lower 1/3 of lemma, not or briefly surpassing glumes in P.rosei). We include a generic key to distinguish the species of Podagrostis from other similar genera in Latin America and a key to distinguish the species of Podagrostis now accepted as occurring in these areas.

usually awnless or with a short straight awn 0.2-0.6 mm long, inserted medially or in the upper 1/3 of the lemma, not surpassing the glumes. These characters are also found in the species Agrostis liebmannii (E. Fourn.) Hitchc. and A. rosei (awn well-developed, straight or geniculate and inserted in lower 1/3 of lemma, usually not surpassing glumes in A. rosei) from mountains of central and southern Mexico, A. exserta Swallen from high-elevation grasslands of Guatemala, and A. bacillata Hack. and A. trichodes (Kunth) Roem. & Schult. from high-elevation páramo grasslands of Costa Rica and Panama, or northwest South America, respectively. The possible affinity of some of these species to Podagrostis, based on the presence of a rachilla prolongation, has been suggested (Pohl and Davidse 1994;Briceño 2010), and the placement of A. rosei in the plastid tree in Saarela et al. (2017) provided molecular support for this idea. All other Agrostis taxa with well-developed paleas in Mexico, Central America and northwest South America, with which these species could possibly be confused (because their paleas sometimes exceed 2/3 the length of their lemmas), are exotics introduced from the Old World (i.e. A. alba L.; A. capillaris L.; A. castellana Boiss. & Reut.; A. gigantea Roth; A. stolonifera L.) that lack a rachilla prolongation and have florets that are 1/3-3/4 the length of the glumes, and paleas ranging from 2/5 to 2/3 (rarely reaching to ¾) the length of the lemmas. The other native Agrostis species from the region we are discussing have shorter, often rudimentary or absent paleas.
In a large unpublished molecular DNA sequence study using three plastid gene regions (rpl32-trnL spacer, rps16-trnK spacer, and rps16 intron), Romaschenko et al. (pers. comm.) found that A. bacillata and A. rosei were closely related to other taxa of North American Podagrostis [P. aequivalvis; P. humilis (Vasey) Björkman; P. thurberiana (Hitchc.) Hultén]. These form a clade sister to Agrostis and Polypogon. Saarela et al. (2017) also reported a similar result for A. rosei in their plastid tree, which found the taxon to be part of a well-supported clade with four Chinese species of Deyeuxia, and Calamagrostis bolanderi + Podagrostis aequivalvis. Some of the aforementioned Chinese Deyeuxia's and C. bolanderi from California remain to be sampled using the same markers used in this study to clarify their position. Although C. bolanderi's placement in a strongly supported lineage with Podagrostis aequivalvis (Saarela et al. 2017) provides support for its transferal to Podagrostis, it may represent a separate hybrid between Podagrostis and Calamagrostis.
Nuclear ribosomal internal transcribed spacer DNA sequences of all these species resolved within Calamagrostis sensu Peterson et al. (2019), which is also congruent with placement of P. aequivalvis in the ITS and ITS+ETS tree and of A. rosei in the ITS tree in Saarela et al. (2017). Saarela et al. (2017) also mentioned A. rosei to be placed outside of two strongly supported clades that include all sampled species of Agrostis, Polypogon and one species of Lachnagrostis in their more well-resolved, albeit more poorly sampled, ITS-ETS tree (Saarela et al. 2017: 65, not shown in Saarela et al. 2017: fig. 7), further confirming the distinctiveness of this taxon. The contrasting nrDNA and plastid placements indicate Podagrostis is reticulate in origin between Calamagrostis and a sister lineage to Agrostis plus Polypogon, and may yet extend to Asian elements.
The molecular results support our transfer of these and other morphologically similar Agrostis species, A. exserta, A. liebmannii, and A. trichodes, to Podagrostis. We pro-1 Spikelets disarticulating below the glumes, the glumes and floret, and often part of the pedicel, falling together as a unit; glumes awned or muticous ....2 -Spikelets disarticulating above the glumes, the glumes remaining on the inflorescence after the florets have fallen; glumes acute to acuminate, not awned . Floret equaling or subequaling the glumes, sometimes slightly shorter but reaching past ¾ the length of the glumes, usually with a short rachilla prolongation emerging behind the palea (sometimes absent in many florets of P. rosei so check many spikelets); paleas well-developed, usually reaching from (2/3) ¾ to almost the apex of the lemma; panicles 1-6.5(-11) cm long (up to 18 cm in the Mexican species P. liebmannii and P. rosei); lemmas muticous or with a short straight awn 0. Lemmas unawned or with a short straight awn, usually < 0.5 mm long, inserted in the upper half of the lemma, not or barely exceeding the glumes (awn well-developed, 1.6-2 mm long, inserted in lower 1/3 of lemma, straight or geniculate and usually not surpassing glumes in Podagrostis rosei, but then callus glabrous, rachilla very short, < 0. Leaves; ligules 0.2-5.5 mm long, hyaline, glabrous, smooth or lightly scabrous, apices truncate, obtuse, acute or acuminate, entire to lacerate; blades involute, folded, or flat. Inflorescence 1-12 cm long, a panicle, lax and open to loosely to moderately densely contracted; panicle branches and pedicels glabrous, often smooth or infrequently scaberulous. Spikelets 1-4.2 mm long, 1-flowered, disarticulating above the glumes, weakly laterally compressed; glumes equal or subequal, the lower often longer than the upper, equaling or subequaling the length of the floret or slightly longer, persisting on the plant after the florets have fallen or sometimes readily caducous, glabrous, keel smooth or usually scabrous at least distally, lateral veins smooth or slightly scabrous distally, surfaces usually smooth, less often scabrous; lower glume 1-or 3-veined; upper glume 1-(2-) or 3-veined; floret 1 in number, sessile, subequaling to equaling the apex of the glumes; lemmas membranaceous, often slightly thicker than the glumes, dorsally rounded, 3-or 5-veined, lateral veins not evident to distinct, glabrous, smooth or scabrous, apex muticous or with a short straight awn 0.2-0.6 mm long, inserted medially or in the upper 1/3 of the lemma, not surpassing the glumes, (awn welldeveloped, 1.6-2 mm long, inserted in lower 1/3 of lemma, straight or geniculate and usually not surpassing glumes in P. rosei); paleas well-developed, reaching from (2/3) ¾ to subequaling the lemma, keels obscure to distinct, glabrous, smooth; calluses rounded, blunt, usually glabrous, or with two short lateral tufts of hairs to 0.5 mm long in some species, abaxially smooth; rachilla prolongation present, slender, varying from rudimentary to 2/3 the floret in length (obscure or absent in many P. rosei spikelets), glabrous or sometimes with short strict hairs to 0.3 mm long emerging only distally, smooth or scaberulous. Flowers perfect; lodicules 2 in number; anthers 3 in number, 0.3-1.6 mm long (-2.2 mm long in P. colombiana); ovaries glabrous. Caryopses slightly shorter to equaling the lemmas, concealed at maturity, subterete to fusiform, hardened, sulcus distinct; hilum punctiform to narrowly ovoid; embryo c. ¼-1/3 length of the caryopsis; endosperm solid (information on caryopses taken from Harvey 2007, Rúgolo de Agrasar 2012 and P. trichodes specimens). 2n = 14 (in P. aequivalvis, P. humilis, P. thurberiana, P. rosei) or 28 (P. bacillata).
Distribution and ecology. New World i.e. North, Central, and South America. Found in cold and wet, often high-elevation environments.
Notes. The taxonomic disposition of Podogrostis as part of Agrostis or a separate genus has long been an obstacle to transfer of the species to the genus. Now that molecular evidence has confirmed the independence of these two genera (Saarela et al. 2017; Konstantin Romaschenko unpublished data) for the type species as well as other species from North America, we feel confident that the genus can be expanded based on shared morphological characteristics. The genus is here considered to contain at least ten distinct species (Podagrostis aequivalvis, P. bacillata, P. colombiana, P. exserta, P. humilis, P. liebmannii, P. rosei, P. sesquiflora, P. thurberiana, P. trichodes). Aside from the characters mentioned in the key above, species of Podagrostis from Guatemala to NW South America can be easily distinguished from Agrostis species with well-developed paleas by the leaf blades being involute or convolute, while being generally flat in the Agrostis species with well-developed paleas (A. capillaris generally has basal blades involute and culm blades flat). Further distinction of P. exserta and P. trichodes from other species of Agrostis with well-developed paleas in Guatemala and NW South America can be made by the very short panicles, usually < 5 cm long, versus panicles > 5 cm long in the latter.
In high-elevation Guatemala and páramos of Central and NW South America, species are known to only have a densely tufted or tussock-forming habit with intravaginal innovations. A loosely tufted habit and extravaginal innovations, that often leads to a rhizomatous or subrhizomatous habit, is only found in species from Mexico (P. liebmanni, P. rosei), the USA and Canada (P. aequivalvis, P. thurberiana) and from Chile and Argentina (P. sesquiflora).

Key to the species of Podagrostis that are accepted in Latin America
Distribution and ecology. Costa Rica and Panamá, páramo grasslands, 2200-3900 m alt. Pohl (1980)  Notes. The possible affinity of Agrostis bacillata to Podagrostis was mentioned previously (Pohl and Davidse 1994;Briceño 2010), with Pohl and Davidse (1994) recommending transfer of A. bacillata to Podagrostis. The species is similar to P. trichodes and P. exserta (see notes under these taxa on how to differentiate them). The character of adaxial leaf blade surface with conical trichomes intermixed with scabers across a scaberulous surface, mentioned by Pohl and Davidse (1994) to be a key character for differentiating P. bacillata from P. exserta, was not found in any of the Costa Rican specimens studied at US, including specimen Pohl 10693 that was cited by Pohl and Davidse (1994). All specimens studied of this species were generally densely scabrous on the veins of the adaxial blade surface, with short to long and robust scabers of simi-lar consistency to the abaxial surface. This could be attributed to a difference in interpretation by the authors, although similar long scabers, in a similar density, were found on the adaxial leaf blade surface of specimens of P. exserta, meaning this character is not considered useful for species delimitation of these taxa. Instead, we found that a key character for differentiating the two species was the presence or absence of scabrocities on the abaxial leaf blade surface, with P. bacillata usually being densely scabrous with short hooks while P. exserta is smooth.
Additional specimens examined. Guatemala. Huehuetenango: Sierra de los Cuchumatanes, alpine areas in vicinity of Tunima, 3400-3500 m alt., 7 July 1942, J. Notes. Similar in general habit to P. trichodes (see notes under this species for how to distinguish them). Podagrostis bacillata also has smooth panicle branches and pedicels and bears very similar spikelet characteristics to P. exserta, with both having spikelets usually measuring > 1.5 mm long, with smooth glumes apart from the keel being lightly scaberulous, and smooth lemmas. Podagrostis bacillata can be distinguished from P. exserta principally by the culms having at least one visible elongated internode, 4-13 cm long, with usually at least one node exserted from the sheaths (vs. usually no visible elongated internodes or nodes, with the distalmost internode usually < 1 cm long in P. exserta), leaf blade abaxial surface lightly to usually densely scabrous (vs. smooth in P. exserta), leaf blades usually longer, 2-15 cm long, forming a basal mat reaching c. 6-17 cm tall (vs. usually < 4 cm long, forming a basal mat reaching c. 3-6 cm tall in P. exserta), ligules 1.7-4.3 mm long (vs. 0.8-2.5 mm long in P. exserta), and a rachilla prolongation 0.3-1.4 mm long (vs. 0.3-0.5 mm long in P. exserta), (also see notes under P. bacillata). However, one specimen (Steyermark 50216) did have a moderately long internode at c. 4 cm long, as well as slightly longer leaf blades to 5.5 cm long, but could be differentiated based on the short ligules, < 1.4 mm long, short panicles < 3 cm long, and, crucially, the leaf blade abaxial surface being smooth, with scabers only present on the adaxial surface.
The possible affinity of A. exserta to Podagrostis was mentioned previously (Pohl and Davidse 1994;Briceño 2010), with Pohl and Davidse (1994) recommending transfer of A. exserta to Podagrostis. Despite repeated efforts by different researchers (e.g. P. Barbera, Y. Herrera, P.M. Peterson, J. R Reichman, K. Romaschenko, L.S. Watrud, pers. comm.) to sequence leaf samples from herbarium specimens of this species, none have been successful to date largely due to the available specimens having mostly aged, brownish leaves. This may be a characteristic of the species in general, with only new fresh shoots being found very early in the growing season and becoming brown at maturity. Successful molecular sampling of this species is necessary. Description. Tufted perennial forming lax tufts, with the basal foliage reaching c. 11 cm tall and inflorescences well-exserted from the basal foliage. Tillers extravaginal. Culms 35-80 cm tall, erect, simple, delicate; nodes and internodes terete, nodes smooth, internodes and segment below the panicle smooth throughout (or smooth proximally and lightly scaberulous towards their apices in Moore 3339), usually with at least 1 or 2 elongated internodes visible, with 1-2 nodes exposed at flowering, uppermost internode c. 5.5-11.2 cm long, longer than the sheath. Leaves basal and cauline; sheaths terete, glabrous, lower sheaths tending to be smooth, upper sheaths lightly to densely scabrous with short hooks; flag sheath 8-11.5 cm long; basal sheaths 0.5-1 cm long, striate, becoming fibrous, smooth; ligules c. 0.5-4 mm long, membranaceous or scareous, usually strongly decurrent with the sheath, abaxially scabrous; upper culm ligules 1.5-4 mm long, obtuse to acute, sometimes slightly erose towards the apex; ligules of tillers shorter to those of the culm, c. 0.5-1 mm long, truncate to acute; blades 2-8.6 cm long, (0.5-)1-3.5 mm wide in diameter, flat, flaccid to firm, basal blades sometimes very narrow, abaxial surfaces glabrous, smooth to lightly scabrous, or usually more densely scabrous further up the culm, adaxial surfaces glabrous, smooth to lightly scabrous on the veins, scaberulous further up the culm, edges scaberulous. Panicles 7-18 × (1-)2.5-7 cm, open to slightly congested following anthesis, usually ovoid; panicle branches ascendant to patent, branched above the middle, filiform, with spikelets not present near the base, smooth, longest branches 2-4.7 cm long; pedicels 1.5-5 mm long, usually longer than the length of the spikelets, divaricate, smooth or lightly scaberulous. Spikelets (1.8-)2-2.1 mm long; glumes remaining on the inflorescence at maturity, equal or subequal, the lower usually slightly longer than the upper, subequaling the length of the floret to 0.4 mm longer, lanceolate, slightly keeled, apices acute, glabrous, keels lightly scaberulous just in the distal 1/3, surfaces smooth; lower glume 1-(or 3-)veined, lateral veins, if present, vestigial; upper glume 1-(or 3-)veined, lateral veins, if present, vestigial; lemmas 1.7-2 mm long, glabrous, smooth, strongly 5-veined with excurrent prominent veins, apex broadly acute, awn absent; paleas well-developed, 1.4-1.9 mm long, usually reaching from ¾ to subequaling the lemma, keels obscure, smooth, apex bifid and sometimes erose; rachilla prolonged from the base of the floret, 0.3-0.5 mm long, glabrous, smooth. Calluses not or slightly elongated, 0.05-0.1 mm long, glabrous, smooth. Flowers; lodicules c.0.3-0.4 mm long, lanceolate with acuminate apices, not lobed; anthers 3 in number, 0.6-1 mm long. Caryopses not seen. 2n= unknown.
Distribution and ecology. Mexico, endemic. The authors have only verified specimens from Hidalgo, Puebla and Veracruz states of central Mexico, with Beetle (1983), Dávila et al. (2018), and Sánchez-Ken (2019) mentioning the species to range from Durango state in the north to Oaxaca state in southern Mexico. Found in humid areas of pine and fir forests, Sphagnum bogs, and by streams, 2100-2300 m (Beetle 1983).
Notes. Beetle (1983) appears to consider Agrostis durangensis Mez a synonym of A. liebmannii, and states A. liebmannii to be distributed as far north as Durango state based on the type locality of A. durangensis. However, we consider A. durangensis to be a synonym of A. exarata Trin. and have only verified specimens from as far north as Hidalgo state. Herrera-Arrieta (2001) cite A. liebmannii for Durango state based on specimen Palmer 190 (US00486604), which is treated here as A. exarata. Herrera-Arrieta (2014), Dávila et al. (2018) and Sánchez-Ken (2019) also mention Agrostis liebmannii to be found as far north as Durango state, but do not include voucher specimens and may have based this on Beetle's (1983) and Herrera-Arrieta's (2001) treatments. Certain characteristics in Beetle's (1983: 82) description of A. liebmannii also do not fit the specimens examined, which may be due to the author's inclusion of A. durangensis in the species circumscription. Spikelet size of 2.5 mm mentioned by Beetle (1983: 82) does not fit the specimens studied which had spikelets (1.8-)2-2.1 mm long, although Beetle's (1983: 73) key to species separates A. liebmannii from A. hiemalis var. laxiflora (Michx.) Beetle (= Agrostis scabra Willd.) based on spikelets being c. 2 mm long and shorter than 2.5 mm long. Beetle's (1983) mention that the tiller blades are more-orless involute was also not seen, although specimen Moore 3339 (US00486609) was intermixed with another species with involute blades, which might explain this.
Podagrostis liebmannii bears close affinity to P. thurberiana, a North American species that is found as far south as California (Hitchcock et al. 1969;Harvey 2007). These similarities include a) the overall habit, with tall culms, loosely tufted and subrhizomatous habit with extravaginal shoots; b) spikelet morphology, with spikelets usually < 2.3 mm long, lemmas with excurrent prominent veins and paleas almost subequalling the lemma; c) panicles open and becoming slightly congested following anthesis; d) flat leaf blades. Podagrostis liebmannii can be distinguished from the aforementioned species by a) panicles generally much larger, 8-18 × (1-)2.5-7 cm, with patent panicle branches at anthesis (vs. 5-14 × 0.2-3 cm, panicle branches usually ascending at anthesis in P. thurberiana); b) callus glabrous (vs. with short hairs to 0.5 mm long emerging from the basal side-ridges of the callus in P. thurberiana); c) rachilla glabrous, smooth (vs. short hairs to 0.3 mm long emerging from the apex of the rachilla in P. thurberiana). Fournier (1886: 97) cited two specimens, Liebmann 710 and Botteri 93, in the protologue but only indicated the P herbarium for the Botteri 93 specimen. As we are sure that Fournier saw the Botteri 93 specimen at P, we lectotypify on this collection.
Because both the Botteri 93 and Liebmann 710 material included just an inflorescence culm and part of the flag leaf and did not show the basal parts of the plant, we also epitypify the lectotype on Liebmann s.n. (US00595641) that was collected on the same date and at the same locality as the Liebmann 710 collection and includes the basal portion of the plant to help interpret the lectotype. The epitype Liebmann s.n. (US00595641) cited here may in fact be a duplicate of the Liebmann 710 syntype that Fournier (if he ever saw it) did not annotate at the Copenhagen herbarium. The US specimen identified as Agrostis liebmannii ("Apera" not mentioned) was catalogued as Plantae mexicanae Liebmann #12591; these catalogue numbers are often followed by Liebmann's field numbers such as the handwritten "710". The Copenhagen herbarium does not have a Liebmann duplicate bearing either of these numbers, or either of the synonyms. Description. Tufted perennial forming lax tufts, with the basal foliage reaching c. 4-9 cm tall and inflorescences well-exserted from the basal foliage. Tillers extravaginal. Culms 34-65 cm tall, erect or geniculate at the base, simple, delicate; nodes and internodes terete, nodes smooth, internodes and segment below the panicle smooth throughout, usually with at least 2 elongated internodes visible, with 1-3 nodes exposed at flowering, uppermost internode c. 5.6-9 cm long, longer than the sheath. Leaves basal and cauline, somewhat dimorphic with basal leaf blades filiform, flat or folded, while culm blades are wider and flat; sheaths terete, glabrous, lower sheaths smooth, upper sheaths smooth to very lightly scaberulous with short hooks; flag sheath 9-11.5 cm long; basal sheaths c. 1-2 cm long, striate, becoming fibrous, smooth; ligules c. 1-3 mm long, membranaceous to scarious, strongly decurrent with the sheath, sometimes lacerated, abaxially smooth or very lightly scaberulous; upper culm ligules 1.5-3 mm long, obtuse, sometimes deeply lacerated or erose towards the apex; ligules of tillers shorter to those of the culm, c. 1-1.3 mm long, truncate to obtuse; blades 1.5-9 cm long, 0.2-2.6 mm wide when opened out, basal blades 1.5-7 cm long, 0.2-0.6(-1) mm wide when opened out, usually narrower than the culm blades, filiform, flat or folded, flaccid to slightly firm, culm blades (2.8-)3.5-9 cm long, 1-2.6 mm wide, flat or sometimes slightly convolute towards the apices, flaccid to moderately firm, abaxial and adaxial surfaces glabrous, smooth or usually lightly to moderately scabrous on the veins with short hooks, edges scaberulous to scabrous. Panicles 8-14 × (1-)2.5-9 cm, open to slightly congested when immature, usually ovoid; panicle branches ascendant to patent, branched above the middle, filiform, with spikelets not present near the base, smooth, longest branches 2.5-7 cm long; pedicels 1-2.5 mm long, shorter or longer than the length of the spikelets, divaricate, smooth or lightly scaberulous. Spikelets 1.9-2.3 mm long; glumes remaining on the inflorescence at maturity, equal or subequal, the lower usually slightly longer than the upper by up to 0.2 mm, subequaling the length of the floret or to 0.2 mm longer, lanceolate, slightly keeled, apices acute, glabrous, keels completely smooth or scaberulous just in distal 1/3, surfaces smooth; lower glume 1-(or 3-)veined, lateral veins, if present, vestigial; upper glume 1-(or 3-) veined, lateral veins, if present, vestigial; lemmas 1.6-1.8 mm long, glabrous, smooth, strongly 5-veined with slightly excurrent prominent veins distally, apex broadly acute with 4 deltoid teeth, awn present, 1.6-2 mm long, straight, flexuous or geniculate, inserted in the lower 1/3 of the lemma, sometimes inserted basally c. 0.3 mm from the base, reaching the apex of the lemma, the glumes or sometimes briefly surpassing the glumes, glabrous, smooth proximally, scabrous distally; paleas well-developed, 1.3-1.7 mm long, usually reaching at least ¾ the length of the lemma to subequaling the lemma apex, keels obscure, smooth, apex bifid and sometimes erose; rachilla rudimentary or prolonged from the base of the floret, to 0.3 mm long, glabrous, smooth.  Muhlenbergia andQuercus, 23°28'31.4"N, 104°55'3.6"W, 2630 m alt., 25 Sep. 2005, P.M. Peterson 19124 (US00900682).
Notes. This species is distinct from all other species of Podagrostis currently circumscribed by the presence of a well-developed awn inserted in the lower dorsal surface of the lemma. Molecular data supports its inclusion in Podagrostis (Konstantin Romaschenko, pers. communication) with morphological attributes also corroborating this such as the florets subequalling the apices of the glumes, a well-developed palea > ¾ the length of the lemma, and completely glabrous spikelets. The lax and open, large panicles, and completely glabrous and mostly smooth spikelets, pedicels and panicle branches places it very close to P. liebmannii. Description. Tufted perennial forming short dense tufts, with the basal mats reaching c. 4-11 cm tall and inflorescences well-exserted from the basal foliage. Tillers intravaginal. Culms 7-20(-30) cm tall, erect, simple, delicate; nodes and internodes terete, smooth, nodes usually hidden in the sheaths with 0(-1) nodes exposed at flowering, uppermost internode usually < 1 cm long, usually not longer than the sheath. Leaves generally basal; sheaths terete, glabrous, finely to densely scabrous; flag sheath 2-5.6 cm long; basal sheaths 0.7-1.5 cm long, striate, becoming fibrous; ligules 0.7-1.7(-2.5) mm long, membranaceous, slightly to usually strongly decurrent with the sheath; flag ligules acute with a obtuse to truncate apex, usually slightly erose towards the apex; ligules of tillers 0.7-1.2 mm long, truncate; blades 1-4 cm long, 0.3-0.4 mm wide in diameter, involute or convolute, acicular to capillaceous and filiform, usually curved, abaxial surface glabrous, finely to densely scabrous, adaxial surface glabrous, lightly to usually densely scabrous with prickle hairs usually short, less often long and robust. Panicles 2-5(-6) × 1-2(-3) cm, open, ovoid; panicle branches ascendant to patent, branched above the middle, filiform, with spikelets not present near the base, smooth to usually scaberulous, longest branches 0.8-3 cm long; pedicels 1-2 mm long, usually longer than the length of the spikelets, divaricate, smooth to usually lightly scabrous. Spikelets 1-1.5 mm long; glumes remaining on the inflorescence at maturity or one or both readily caducous at maturity and falling before the floret, equal or subequal, the lower often slightly longer than the upper or less often vice versa, almost equaling the length of the floret or slightly longer, oblong-lanceolate, slightly to distinctly keeled, apex obtuse to acute, glabrous, keels scabrous just in the distal 1/3 to throughout their length, surfaces smooth a scabrous distally; lower glume 1-veined; upper glume 1-or 3-veined; lemmas 1-1.5 mm long, glabrous, moderately to densely scabrous ('smooth' possibly mentioned by Tovar 1993!), sometimes granulose, faintly to strongly 5-veined, apex obtuse, awn lacking or to 0.5 mm long, straight, inserted medially or in the upper half of the lemma; paleas (0.7-)0.9-1.3 mm long, usually reaching from ¾ to subequaling the lemma, less often reaching 2/3 the length of the lemma, keels obscure to fairly prominent, smooth, apex bifid and erose; rachilla absent or prolonged from the base of the floret (sometimes lacking in a small number of spikelets within the inflorescence), 0.2-0.5 mm long, glabrous, smooth to scabrous. Calluses 0.05-0.1 mm long, slightly elongated or not, glabrous. Flowers; lodicules c. 0.4 mm long, lanceolate with acute apices, not lobed; anthers 3 in number, 0.4-1 mm long. Caryopses c. 1 mm long, subterete, sulcus distinct, dark brown with apex dark; hilum 0.25 mm long, narrowly ovoid; endosperm solid. 2n = unknown.

Podagrostis trichodes
Distribution and ecology. Bolivia?, Colombia, Ecuador?, Peru, Venezuela, 2800-4500 m alt. Relatively humid high-Andean puna grasslands of southern and central Peru and páramo grasslands of Ecuador, Colombia and Venezuela. Tovar (1993) mentions that the species may also occur in Bolivia, presumably in high-elevation cool and humid sites such as the Bolivian Yungas which have been referred to as páramo (García and Beck 2006), although no specimens have been verified by the authors. No specimens at the US herbarium were found from Ecuador after careful searching by the first author, although it is mentioned to occur there (Hitchcock 1927;Tovar 1993;Jørgensen and Ulloa-Ulloa 1994;Jørgensen and León-Yánez 1999;Luteyn 1999). In Colombia, the taxon is known from multiple collections from páramos of the Cordillera Oriental of the Colombian Andes, belonging to Departamentos Cundinamarca, Boyacá, Santander, Santander Norte and Cesar. We present new regional records of the species for Departamentos Santander Norte and Cesar which are not mentioned in the recent checklist (Giraldo-Cañas et al. 2016). Giraldo-Cañas et al. (2016) also cite Agrostis trichodes for Departamento Meta, in the southernmost part of the Cordillera Oriental, and Departamento Magdalena, which contains páramos of the Sierra Nevada de Santa Marta, although no specimens have been verified. In Venezuela, the species is found in páramos of the Cordillera de Merida.
Usually found in frequently grazed areas where its short basal tufts of leaves are difficult for grazers to reach. Specimens from Peru appear to be found in humid habitats, with the specimens studied by Tovar (1993) collected from the Abra Malaga of the Cusco region which is relatively humid and receives updrafts of moisture-laden air from the Amazon (Sylvester et al. 2014(Sylvester et al. , 2017. While P. trichodes is relatively common in páramos of Colombia and Venezuela, it may be that this species is much rarer further south and, in Peru, belongs to a thin band of humid páramo-like vegetation that extends from the Peruvian Jalca down through southern Peru and into the Bolivian Yungas (Antoine Cleef, pers. communication).
Other specimens examined.   Notes. Briceño (2010) noted the possible relationship of Agrostis trichodes to Podagrostis based on the rachilla prolongation. While studying specimens of A. trichodes from páramos of Colombia and Venezuela, SPS noted certain characteristics differed from the type collected in Peru, the protologue, and the description in the treatment of grasses of Peru (Tovar 1993). These characteristics, including presence of a rachilla prolongation emerging from the base of the florets, and lemmas sometimes with a short dorsally inserted awn, are also shared by A. bacillata and A. exserta, and highlight the connection of this species to Podagrostis.
The character of awn presence was not noted for this species by Hitchcock (1927) nor Tovar (1993), although Briceño (2010) mentions this for Venezuelan material. While Hitchcock (1927) highlights the rachilla prolongation as a crucial character for distinguishing this species from other Agrostis, Tovar (1993) did not mention it. This information is also lacking from the protologues of both Vilfa trichodes and Agrostis bogotensis. The Vilfa trichodes isotype at HAL bears spikelets which lack a rachilla extension, and lemmas that lack awns (Marcus Lehnert and Natalia Tkach, pers. communication). It appears that Oscar Tovar, when preparing his treatment of the grasses of Peru (Tovar 1993), had only seen the US isotype fragment, which lacks florets. His mention that the glumes are 'glabrous' (by which Tovar meant glabrous and smooth) raises ambiguity, although most other characters found in the description and illustration match. The flag leaf ligule of the US isotype fragment reached 1.5 mm long, while Tovar (1993) mentions the ligule to measure 2-2.5 mm long, with most material studied from Colombia and Venezuela having flag leaf ligules to 1.7 mm long, with those of the tillers c. 0.5 mm long. Tovar's (1993) description seems to have been based largely on Tovar and Rivas-Martínez 8076, 8080 from Abra Malaga of the Cusco region of southern Peru, which were not seen by us. The first author visited the Abra Malaga site to conduct extensive field surveys and botanical collecting during different seasons from 2010-2013 (Sylvester et al. 2014(Sylvester et al. , 2017 but no specimens were encoun-tered. Aside from the type, no specimens from Peru have been located despite careful searching through the US herbarium. Podagrostis trichodes closely resembles P. exserta and P. bacillata, considered endemic to alpine grasslands of Guatemala or páramos of Costa Rica and Panama, respectively (Pohl and Davidse 1994). Key similarities include: a) an overall similar habit (i.e. short tufted herbs with exserted open panicles); b) involute or convolute, acicular or filiform leaf blades; c) presence of a short glabrous rachilla extension emerging from the base of the floret; and d) a short awn often found inserted medially on the lemma dorsal surface. Both P. bacillata and P. exserta have smooth panicle branches, pedicels, glume surfaces (with only the keels being lightly scaberulous), and lemma surfaces while these are usually lightly to densely scabrous in P. trichodes, although specimens have been encountered with almost smooth panicle branches and pedicels [e.g., M.C. Gomez 1 (US3534984), H.G. Barclay 9685 (US3044346), 9546 (US3096576)]. The overall habit of P. exserta more closely resembles that of P. trichodes than P. bacillata, in lacking a visible elongated culm internode and having a shorter panicle (< 5 cm long vs. 4-11 cm long in P. bacillata). However, P. exserta can be differentiated from P. trichodes in having smooth leaf blade abaxial surfaces, lemma surfaces, panicle branches, and pedicels (vs. usually scaberulous to densely scabrous, panicle branches and pedicels infrequently smooth in P. trichodes), its glume keels and surfaces being mostly smooth with only few prickle hairs found on the keel distally (vs. glume keels often densely scabrous for most their length with surfaces often scabrous distally in P. trichodes), and larger spikelets (usually 1.5-2 mm long vs. 1-1.5 mm long in P. trichodes).
Specimens from páramos of Departamento Boyacá, Colombia, were noted to have the unusual character of glumes being readily caducous at maturity and falling before the floret, with mature inflorescences lacking glumes and only the florets remaining on the pedicels. It is not clear whether this may be a reaction to a pathogen or whether it is taxonomically informative since other specimens sometimes lack this character.
Certain specimens of Freire Apolliniaire are annotated as isotypes of Agrostis bogotensis at P (P00740431 [image!]) and NY (NY00327650 [image!], NY00688633 [image!]) that differ in collection dates, collection numbers, and/or localities from the holotype, with NY00688633 also obviously not the same species. These should be disregarded as type material and reexamined. Apolliniaire s.n. K000308373 may be an isotype but the full collection date is missing to help clarify this.