Research Article |
Corresponding author: Steven P. Sylvester ( steven_sylvester@hotmail.com ) Academic editor: Maria Vorontsova
© 2020 Steven P. Sylvester, Paul M. Peterson, Konstantin Romaschenko, William J. Bravo-Pedraza, Lia E. Cuta-Alarcon, Robert J. Soreng.
This is an open access article distributed under the terms of the CC0 Public Domain Dedication.
Citation:
Sylvester SP, Peterson PM, Romaschenko K, Bravo-Pedraza WJ, Cuta-Alarcon LE, Soreng RJ (2020) New combinations and updated descriptions in Podagrostis (Agrostidinae, Poaceae) from the Neotropics and Mexico. PhytoKeys 148: 21-50. https://doi.org/10.3897/phytokeys.148.50042
|
Based on morphological study and corroborated by unpublished molecular phylogenetic analyses, five grass species of high-mountain grasslands in Mexico, Central and South America, Agrostis bacillata, A. exserta, A.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 Apera liebmannii 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.
Basado en estudios morfológicos y corroborado por datos no publicados de análisis filogenéticos, las cinco gramíneas de alta montaña de los pastizales en México, Centroamérica y Sur América Agrostis bacillata, A. exserta, A. liebmannii, A. rosei, y A. trichodes, son transferidos a Podagrostis incrementando a diez el número de especies en el nuevo mundo de este reconocido género. El nombre de Apera liebmannii también es lectotipificado y epitipicado. Proporcionamos una descripción actualizada del género Podagrostis, y descripciones actualizadas de las especies, imágenes y comentarios sobre las nuevas combinaciones. Las características diagnósticas que diferencian a Podagrostis de Agrostis son: a) pálea de 2/3-¾ hasta casi el ápice de la lemma; b) espiguillas, generalmente casi iguales en longitud a las glumas o de al menos ¾ la longitud de las glumas; c) extensión de la raquilla presente y emergiendo desde debajo de la base de la pálea como un trozo corto y delgado (desde rudimentario hasta de 1.4 mm de largo, a veces oscuro en la mayoría de los flósculos en P. rosei), liso o escabérulo, glabro o piloso distalmente (pelos < 0.3 mm de largo); d) lemmas generalmente sin arista, o a veces con arista corta y recta de 0.2–0.6 mm de largo, insertada medialmente o en el tercio superior de la lemma, sin sobrepasar las glumas (arista bien desarrollada, recta o geniculada e insertada en la parte inferior 1/3 de lemma, no o superando brevemente las glumas en P. rosei). Incluimos una clave para distinguir Podagrostis de otros géneros similares presentes en América Latina y una clave para distinguir las especies de Podagrostis ahora aceptadas por estar presentes en estas áreas.
Agrostis, Andes, Central America, Colombia, Ecuador, páramo, Peru, Venezuela
Agrostis L. and Podagrostis (Griseb.) Scribn. & Merr. both belong to the tribe Poeae R.Br., subtribe Agrostidinae Fr. s.s. (
Morphologically, these taxa of Podagrostis differ from currently circumscribed Agrostis taxa in the combination of a well-developed, relatively long palea that reaches from (2/3) ¾ to almost the apex of the lemma, florets that usually almost equal the length of the glumes or which at least reach past ¾ the length of the glumes, the presence of a slender rachilla prolongation in all or most spikelets that is smooth or scaberulous, with hairs lacking or distally pilulose (hairs < 0.3 mm long), and lemmas 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 (
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.
Nuclear ribosomal internal transcribed spacer DNA sequences of all these species resolved within Calamagrostis sensu
The molecular results support our transfer of these and other morphologically similar Agrostis species, A. exserta, A. liebmannii, and A. trichodes, to Podagrostis. We propose five new combinations, Podagrostis bacillata, P. exserta, P. liebmannii, P. rosei, and P. trichodes, and provide images, up-to-date descriptions, and notes for each species. We also present a key to distinguish Podagrostis from similar genera in the Neotropics and Mexico, and a key to distinguish Podagrostis species from these areas.
Accepted species follow Soreng et al. (2003 and onwards). Herbarium acronyms follow Index Herbariorum (Thiers, continuously updated). In this treatment, unless otherwise stated, glabrous means without pubescence (in the sense of slender, relatively soft hairs). Smooth indicates no prickle-hairs with broad bases and/or hooked or pointed apices (i.e., pubescence can occur on a smooth surface, and a rough or scabrous surface can be glabrous). Specimens in the herbaria COL, FMB, K, UPTC, and US were reviewed for this study. Beyond types (some only seen in images), only material from herbaria where specimens have been checked and verified by the authors are cited. Parts of the generic key related to taxa of previously circumscribed Calamagrostis s.l. were adapted from
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 | 5 |
2 | Palea < ½ the length of the lemma; glume apices lanceolate or lanceolate-subulate, muticous, mucronulate or awned | Chaetotropis Kunth |
– | Palea equaling or subequaling the lemma; glume apices obtuse or bilobed (Polypogon) or muticous (Cinna), awned or unawned | 3 |
3 | Panicles condensed, generally spikelike; glumes much longer than the lemma; glume apices obtuse or bilobed, awned or unawned; rachilla extension absent | Polypogon Desf. |
– | Panicles open to loosely contracted, somewhat lax; glumes as long as the lemma; glume apices muticous, unawned; rachilla extension usually present as a short glabrous stub | 4 |
4 | Lemma with a subapical awn 5–14.5 mm long; glumes coriaceous, rigid, hispid or scabrous throughout; anthers 3 | Limnodea L.H. Dewey |
– | Lemma unawned or with a subapical awn < 1 mm long; glumes membranous, flexible, glabrous, scabrous only on the keel and sometimes lateral veins; anthers 1 or 2 | Cinna L. |
5 | Rachilla extension absent; palea of varying length; callus glabrous or shortly pubescent with hairs to 0.5 mm long | 6 |
– | Rachilla extension present (cases where it is sometimes rudimentary key both ways), of varying lengths (sometimes very short, and requiring the base of the palea be checked closely to distinguish the structure from hairs) smooth or scaberulous, glabrous or pilulose to pilose, NB. (absent in Calamagrostis llanganatensis Laegaard but then callus hairs reaching from ½ to ¾ the length of the lemma); palea well-developed, generally > 2/3 the length of the lemma; callus glabrous, shortly pubescent, or notably pubescent with long hairs | 9 |
6 | Floret stipitate (lowermost rachilla internode distinctly elongated between the glumes and the floret), stipe 0.2–4 mm long, cylindrical, dilated towards its apex (can be seen at the base of the glumes after the floret has fallen); spikelets > 4 mm long; palea well-developed, subequaling the lemma | Deschampsia P. Beauv. (in part) |
– | Floret sessile (lowermost rachilla internode not, or not noticeably, prolonged between the glumes and the floret), stipe less than 0.2 mm long; spikelets commonly < 4 mm long; palea of varying length, well-developed and subequaling or equaling the lemma to minute/absent | 7 |
7 | Lemma apex terminating in 4 scabrous setae; lemma surface often pilose; lemma with a well-developed geniculate awn inserted in the lower 1/3 and surpassing the glumes; calluses pilulose; caryopsis thin, with liquid endosperm |
Bromidium Nees & Meyen (likely a synonym of Agrostis; |
– | Lemma apex entire or finely dentate with short teeth at the end of each lateral vein; lemma surface glabrous (rarely with a few hairs in Agrostis castellana L.); lemmas muticous, with a short straight awn 0.2–1 mm long, or with a long geniculate and twisted awn to 6+ mm long, inserted basally, medially or in the upper half of the lemma, not surpassing to greatly surpassing the glumes; calluses usually glabrous or with hairs restricted to lateral lines continuous with the basal lemma margins; caryopsis usually rounded, with hardened endosperm | 8 |
8 | 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 0.2–0.6 mm long, inserted medially or in the upper half of the lemma, not surpassing 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 P. rosei) | Podagrostis (Griseb.) Scribn. & Merr. (in part) |
– | Floret notably shorter than the glumes, usually 1/3–3/4 the length of the glumes, rarely longer, without a trace of a rachilla prolongation; paleas well-developed, poorly-developed, or absent, when well-developed reaching from ½–¾ the length of the lemma; panicles often > 5 cm long; lemmas muticous, with a short straight awn 0.2–1 mm long, or with a long geniculate and twisted awn to 6+ mm long, inserted basally, medially or in the upper half of the lemma, not surpassing to greatly surpassing the glumes | Agrostis L. |
9 | Lemmas densely pubescent, with rigid and abundant hairs that cover the lemma veins | 10 |
– | Lemmas glabrous or pilose only at the basal margins, with veins evident at least in the upper part | 11 |
10 | Culms fragile at maturity, inflorescence often disarticulating with age; panicles generally open, with divaricate branching | Lachnagrostis Trin. |
– | Culms slender or stout, not disarticulating with age; panicles contracted or open, without divaricate branching (in species with hairy lemmas) | Peyritschia E. Fourn. (in part) |
11 | Floret stipitate (lowermost rachilla internode distinctly elongated between the glumes and the floret), stipe 0.2–4 mm long, cylindrical, dilated towards its apex (can be seen at the base of the glumes after the floret has fallen); callus and rachilla glabrous (rarely with a few short callus hairs); ligules slightly to strongly decurrent, usually elongated, 4–20 mm long, acuminate, smooth or nearly so, glabrous, entire or laterally cleft | Deschampsia P. Beauv. (in part) |
– | Floret sessile or subsessile (lowermost rachilla internode not, or not noticeably, prolonged between the glumes and the floret), stipe < 0.2 mm long; callus and rachilla glabrous or pubescent; ligules decurrent or not, 0.2–10 (–15) mm long, commonly less than 4 mm long (lateral lobes often exceeding the central part), often scabrous or pubescent, commonly truncate to obtuse | 12 |
12 | 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, < 0.3 mm long, glabrous, plants from Mexico) | 13 |
– | Lemmas with a well-developed usually geniculate and twisted awn (sometimes flexuose in e.g. Apera), > 1 mm long, inserted in the lower or upper half of the lemma, clearly exceeding the glumes | 17 |
13 | Callus and rachilla glabrous [Podagrostis sesquiflora (E. Desv.) Parodi ex Nicora often with short hairs emerging from only the rachilla apex and the basal side-ridges of the callus] | 14 |
– | Callus and rachilla hairy (NB. Rachilla absent in Calamagrostis llanganatensis) | 15 |
14 | Anthers 3 in number, 0.4–1 mm long (to 2.2 mm long in P. colombiana Sylvester & Soreng); spikelets < 4 mm long (sometimes to 4.2 mm long in P. colombiana); panicles 1–6.5(–11) cm long in taxa from Central and South America, 7–17 cm long in P. liebmannii and P. rosei from Mexico; palea keels smooth | Podagrostis (Griseb.) Scribn. & Merr. (in part) |
– | Anthers 3 or 1 in number, 1.2–3 mm long; spikelets 3.5–6+ mm long; panicles usually >11 cm long; palea keels often scabrous, at least in part, sometimes smooth throughout (e.g. C. carchiensis Lægaard) | Calamagrostis Adans. (in part) |
15 | Rachilla absent | Calamagrostis llanganatensis Laegaard |
– | Rachilla present | 16 |
16 | Florets with a short stipe (± 0.15 mm long) between the upper glume and the callus of the floret; both glumes 3-veined; caryopsis hard, hilum linear ± 1/3 the grain in length; plants from the páramo in Ecuador | Laegaardia P.M. Peterson, Soreng, Romasch. & Barberá |
– | Florets sessile; lower glumes 1-veined, upper glumes 1- or 3-veined; caryopses hard to pasty, hilum oval to punctiform < 1/4 the grain in length; plants from various locations, including Ecuadorian páramos | Cinnagrostis Griseb. (in part) |
17 | Anthers 2, or 3 in plants from Mexico and Guatemala; lemma body strongly 5-veined, often puberulent in part | Peyritschia E. Fourn. (in part) |
– | Anthers 1 or 3, if 3 then plants not from Mexico (Calamagrostis guatemalensis Hitchc. from Guatemala); lemma body variously veined, glabrous, sometimes scabrous | 18 |
18 | Panicles open, diffuse; rachilla extension nearly as long as lemma, densely and evenly hairy with hairs 0.5–1.2 mm long; lemmas awned from middle, the awns 2–7.2 mm long, basally twisted, geniculate; callus hairs 0.2–0.8 mm long; leaf blades readily to tardily disarticulating from collars in age (tending to form a J at base after falling), involute, sometimes sinuous; caryopsis hard, hilum linear ± 1/3 the grain in length; lower glumes 1-veined, upper glumes 3-veined and sometimes with 1 or 2 cross-veins between them; plants from páramos of Colombia, Ecuador, and Venezuela | Paramochloa P.M. Peterson, Soreng, Romasch. & Barberá |
– | Panicles open (infrequently diffuse) or contracted; rachilla extension mostly less than ¾ the lemma in length, variously hairy, the hairs 0.5–4 mm long, sometimes reduced or absent proximally; lemmas awned from near base to upper 1/3, the awns 1–10 mm or more long, straight, sinuous or geniculate; callus hairs absent to 4 mm long; leaf blades not disarticulating from collars in age, flat, folded or involute, not sinuous; caryopsis soft or hard; hilum elliptical, oval, round to punctiform 1/5–1/3 the grain in length; lower glumes 1–3-veined without cross-veins between them; plants of various habitats, from Mexico to Tierra del Fuego, Argentina | 19 |
19 | Caryopses hard, distinctly sulcate, hilum 1/6–1/3 the grain in length; lemmatal awns strait or slightly bent, readily distinguished from callus hairs, inserted from near base to middle, not or slightly exceeding the lemma apex; callus hairs 0.1–3 mm long 1/10–3/4 as long as the lemma in length; rachilla glabrous, or sparsely to densely hairy, hairs not reaching lemma apex; panicles contracted; anthers 1 or 3; lodicules entire and lanceolate, sometimes with an isolated lateral lobe, glabrous | Calamagrostis Adans. (in part) |
– | Caryopses soft (liquid or semi-soft) or hard, sulcate (often shallowly) or not, hilum 1/6–1/4 the grain in length (often obscure in species with lipid); lemmatal awns sometimes indistinguishable from callus hairs, straight, sinuous or geniculate, capillary or stout, inserted from base to upper 1/3, usually exceeding the lemma and often exserted from the glumes; callus hairs shorter to exceeding the lemma in length; rachilla hairy, hairs often reaching 3/4 to exceeding the lemma length; panicles contracted or open; anthers 3; lodicules apically bilobate or bidentate, infrequently entire and lanceolate, apical margin sometimes ciliolate or ciliate | Cinnagrostis Griseb. (in part) |
Agrostis sect. Podagrostis Griseb. Fl. Ross. 4(13): 436. 1852.
Agrostis canina var. aequivalvis Trin. (lectotype designated by:
Perennials
, loosely to densely tufted, sometimes forming small tussocks, sometimes subrhizomatous (North American, including Mexico, and Austral South American taxa). Culms 5–90 cm tall, slender. Tillers either extra- or intravaginal. 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 well-developed, 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
New World i.e. North, Central, and South America. Found in cold and wet, often high-elevation environments.
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 (
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. liebmannii, P. rosei), the USA and Canada (P. aequivalvis, P. thurberiana) and from Chile and Argentina (P. sesquiflora).
Calamagrostis meridensis (Luces) Briceño, a species from Venezuelan páramos that is stated to have a rhizomatous habit (
1 | Leaf blades flat; tillers extravaginal, with cataphyllous shoots present; spikelets (1.8–)1.9–2.5 mm long; from Argentina and Chile (P. sesquiflora) or Mexico (P. liebmannii, P. rosei) | 2 |
– | Leaf blades involute or convolute, filiform or acicular; tillers intravaginal, cataphyllous shoots absent; spikelets 1–2 mm long, or 2.8–4.2 mm long in P. colombiana; from NW South America (P. colombiana, P. trichodes), Guatemala (P. exserta), or Costa Rica and Panama (P. bacillata) | 4 |
2 | Panicle contracted and slender, 2–6.5 × 0.25–1 cm, spikelets present from near the base; callus with short hairs 0.1–0.2 mm long; rachilla extension distinct, 0.2–0.4 mm long, often with short hairs distally; from Argentina and Chile | P. sesquiflora (E. Desv.) Parodi ex Nicora |
– | Panicle usually lax and open, less often contracted, 7–18 × (1–)2.5–7 cm, spikelets in the distal 1/3, the lower 2/3 naked; callus glabrous; rachilla extension distinct, 0.3–0.5 mm long, or rudimentary and sometimes absent, glabrous; from Mexico | 3 |
3 | Lemmas with a well-developed awn inserted in the lower 1/3, straight or geniculate, reaching the apex of the lemma or glumes or briefly surpassing them; leaf blades usually dimorphic, those of the tillers filiform and narrow, 0.2–0.6(–1) mm wide when opened out, flat or folded, those of the culm 1–2.6 mm wide, flat or slightly convolute towards their apices | P. rosei (Scribn. & Merr.) Sylvester & Soreng |
– | Lemmas awnless; leaf blades not notably different between tillers and culm, filiform or flat, (0.5–)1–3.5 mm wide | P. liebmannii (E. Fourn.) Sylvester & Soreng |
4 | Panicle contracted and slender, < 1.2 cm wide, spikelets present from near the base; spikelets 2.8–4.2 mm long; upper glume 3-veined; plants forming small tussocks with a basal mat of leaves 5–26 cm tall | P. colombiana Sylvester & Soreng |
– | Panicle lax and open, 1–8 cm wide, spikelets in the distal 1/3, the lower 2/3 naked; spikelets 1–2 mm long; upper glume usually 1-veined, sometimes 3-veined in P. trichodes; plants forming short tufts with a basal mat of leaves often < 10 cm tall (to c. 17 cm tall in P. bacillata) | 5 |
5 | Leaf blade abaxial surface finely to densely scabrous; culms usually with at least one elongated internode visible (not including the terminal culm segment below the panicle), with at least 1 node usually visible at flowering; basal mat of leaves usually 6–13 cm tall, to 17 cm tall; leaf blades 2–15 cm long; ligules 1.7–4.3 mm long; panicles 4–11 cm long, panicle branches and pedicels smooth; spikelets 1.7–2 mm long; glume keels scaberulous just in the distal 1/3, surfaces smooth; lemmas smooth; rachilla 0.3–1.4 mm long; from páramos of Costa Rica and Panama | P. bacillata (Hack.) Sylvester & Soreng |
– | Leaf blade abaxial surface finely to densely scabrous (P. trichodes) or smooth (P. exserta); culms usually without visible elongated internodes (NB. this does not refer to the terminal culm segment below the panicle), with 0(–1) nodes visible at flowering; basal mat of leaves usually < 5 cm tall, to 10 cm tall; leaf blades 1–4 cm long, rarely longer, lightly to densely scabrous or smooth; ligules 1–2(–2.5) mm long; panicles 2–5(–6) cm long, panicle branches and pedicels smooth (P. exserta) or usually lightly to densely scabrous (P. trichodes); spikelets 1–2 mm long; glume keels scabrous just in the distal 1/3 to throughout their length, surfaces smooth or scabrous distally; lemmas smooth (P. exserta) or lightly to densely scabrous (P. trichodes); rachilla 0.2–0.5 mm long; from various localities, not found in Costa Rica or Panama | 6 |
6 | Leaf blade abaxial surface moderately to usually densely scabrous; spikelets 1–1.5 mm long; glume keels scabrous just in the distal 1/3 to throughout their length, surfaces smooth or scabrous distally; lemmas moderately to densely scabrous; panicle branches usually lightly scabrous, infrequently smooth; pedicels usually lightly scabrous, rarely smooth; from Colombia and Venezuela to Peru | P. trichodes (Kunth) Sylvester & Soreng |
– | Leaf blade abaxial surface smooth; spikelets (1.2–)1.5–2 mm long; glume keels scaberulous just in the distal 1/3, surfaces smooth; lemmas smooth; panicle branches smooth; pedicels smooth; from Guatemala | P. exserta (Swallen) Sylvester & Soreng |
Agrostis bacillata Hack., Oesterr. Bot. Z. 52(2): 59. 1902.
Costa Rica. Cerro de la Muerte, Jan. 1897, H. Pittier 10477 (holotype: W (W19160027240 [image!]); isotypes: BAB (BAB00000206 [image!]), BR (BR0000006595845 [image!]), G (G00192030 [image!]), US (US00131726 [not seen], US00131725 [not seen], US00131136 fragm. [not seen]).
Podagrostis bacillata. A Whole plant B spikelets, the center spikelet at anthesis with the palea opened out and the rachilla prolongation visible (indicated with a red arrow) C leaf blades showing the densely scabrous abaxial surface and the central blade opened out to reveal the scabrous adaxial surface. A, B Images of specimen A.M. Evans 145 (US2589766A) courtesy of United States National Herbarium (US) C image of specimen R.W. Pohl 11705A (US3096988).
Tufted perennial forming dense tufts, with the basal mats reaching c. 6–17 cm tall and inflorescences usually well-exserted from the basal foliage. Tillers intravaginal. Culms 10–30(–50) cm tall, erect, simple, delicate; nodes and internodes terete, smooth, usually with at least 1 or 2 elongated internodes visible, with (0–)1–3 nodes exposed at flowering, uppermost internode c. 4–13 cm long, longer than the sheath. Leaves generally basal; sheaths terete, glabrous, smooth to lightly scabrous with very short scabers; flag sheath 4–13 cm long; basal sheaths 1–4 cm long, striate, becoming fibrous; ligules 1.7–4.3 mm long, membranous, slightly to usually strongly decurrent with the sheath; upper culm ligules acute to acuminate with a obtuse to acuminate apex, sometimes slightly erose towards the apex; ligules of tillers similar to those of the culm, sometimes slightly shorter; blades 2–15 cm long, 0.2–0.3(–0.4) mm wide in diameter, involute or convolute, acicular to capillaceous and filiform, straight to slightly curved, abaxial surfaces glabrous, lightly to usually densely scabrous, adaxial surfaces glabrous, lightly to usually densely scabrous on the veins with scabers varying in size from short to long and robust. Panicles (3.5–)4–11.5 × (1–)3–5 cm, open to slightly congested when young, usually ovoid; panicle branches ascendant to patent, branched above the middle, filiform, with spikelets not present near the base, glabrous, smooth, longest branches 1–4.5 cm long; pedicels (1–)2–6 mm long, usually longer than the length of the spikelets, divaricate, glabrous, smooth. Spikelets 1.7–2 mm long; glumes remaining on the inflorescence at maturity, equal or subequal, the lower usually slightly longer than the upper, almost equaling the length of the floret to 0.5 mm longer, oblong–lanceolate, slightly keeled, apex broadly acute, glabrous, keels lightly scaberulous just in the distal 1/3, surfaces smooth; lower glume 1- (or 3-)veined, lateral veins usually vestigial; upper glume 1- (or 2- or 3-)veined, lateral veins usually vestigial; lemmas 1.4–1.6 mm long, glabrous, smooth, faintly 5-veined, apex obtuse, awn lacking or to 0.6 mm long, straight, inserted medially or in the upper 1/3; paleas well-developed, 0.8–1.5 mm long, usually reaching from ¾ to subequaling the lemma, keels slightly obscure, smooth, apex bifid and sometimes erose; rachilla 0.3–1.4 mm long, prolonged from the base of the floret, glabrous, rarely smooth, usually scabrous, sometimes with scabers extending into very short hairs < 0.2 mm long. Calluses 0.1–0.2 mm long, slightly elongated, glabrous, smooth. Flowers; lodicules c. 0.3–0.5 mm long, lanceolate with acute apices, not lobed; anthers 3 in number, 0.8–1 mm long. Caryopses not seen. 2n = 28.
Costa Rica and Panamá, páramo grasslands, 2200–3900 m alt.
Costa Rica. Cartago: Canyon of Rio Tiribi, 3 km NW of Llano Grande, 2200 m, 7 Feb. 1969, R.W. Pohl 11705A (US3096988). Limon: Cordillera de Talamanca, Atlantic slope, Kamuk Massif, páramo north-east of the main Kamuk peak, 9°1'–9°17'N, 83°00'–83°0'W, 3000–3300 m alt., 17–18 Sep. 1984, G. Davidse 29277 (US3041608). San Jose: Cerro Chirripo, treeless páramo SW of and around summit, 11000–12000 ft [3353–3658 m alt.], 24–26 Aug. 1967, A.M. Evans 145 (US2589766A); Cerro de la Vueltas, páramo, 2700–3000 m alt., 29 Dec. 1925–1 Jan. 1926, P.C. Standley 43625 (US1307153); P.C. Standley 43678 (US1307155); Cordillera de Talamanca, Cerro de la Muerte, Asuncion, 3250 m alt., 13 July 1968, R.W. Pohl 10693 (US3096655).
The possible affinity of Agrostis bacillata to Podagrostis was mentioned previously (
Although we have not studied characters of foliar anatomy,
Agrostis exserta Swallen, Contr. U.S. Natl. Herb. 29(9): 404. 1950.
Guatemala. Dept. Huehuetenango: collected in alpine area, vicinity of Tojquia, Sierra de los Cuchumatanes, 3700 m alt., 5 Aug. 1942, J.A. Steyermark 50119 (holotype: US (US00131747 [not seen]); isotype: US (US00131748 [not seen])).
Podagrostis exserta. A Whole plant B Spikelets, the upper glume of the left-hand spikelet has been removed to reveal the rachilla prolongation (indicated with a red arrow) C leaf blade adaxial view, showing scabers on the adaxial surface and smooth abaxial surface of the leaf blade. A Digitized image of specimen J.H. Beaman 3873 (US01247246) courtesy of United States National Herbarium (US) B, C images of specimen G.L. Webster 11826 (US3336153).
Tufted perennial forming short dense tufts, with the basal mats reaching c. 3–6 cm tall and inflorescences usually well-exserted from the basal foliage. Tillers intravaginal. Culms 5–15(–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 (to 4 cm long in Steyermark 50216), usually not longer than the sheath. Leaves generally basal; sheaths terete, glabrous, smooth; flag sheath 2–5.6 cm long; basal sheaths 0.5–1.5 cm long, striate, becoming fibrous; ligules 0.8–2(–2.5) mm long, membranaceous, slightly to usually strongly decurrent with the sheath; upper culm ligules acute with a obtuse to truncate apex, usually slightly erose towards the apex; ligules of tillers similar to those of the culm; blades 1–4(–5.5) cm long, 0.3–0.4(–0.6) mm wide in diameter, involute or convolute, acicular to capillaceous and filiform, usually curved, abaxial surfaces glabrous, smooth, adaxial surfaces glabrous, lightly to usually densely scabrous with scabers usually short, less often long and robust, edges smooth to lightly scabrous with very short hooks. Panicles (1.2–)2–5 × (0.5–)1–2.5 cm, open to slightly congested when young, usually ovoid; panicle branches ascendant to patent, branched above the middle, filiform, with spikelets not present near the base, glabrous, smooth, longest branches 0.3–2 cm long; pedicels (1–)1.5–5 mm long, usually longer than the length of the spikelets, divaricate, glabrous, smooth. Spikelets (1.2–)1.5–2 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 or slightly longer, oblong–lanceolate, slightly keeled, apex broadly acute, glabrous, keels lightly scaberulous just in the distal 1/3, surfaces smooth; lower glume 1- or 3-veined; upper glume 1- or 3-veined; lemmas (1.1–)1.4–1.6 mm long, glabrous, smooth, faintly to strongly 5-veined, apex obtuse, awn lacking or to 0.5 mm long, straight, inserted medially or in the upper 1/3; paleas 0.9–1.3 mm long, notable, usually reaching from ¾ to subequaling the lemma, infrequently reaching 2/3 the length of the lemma, keels usually obscure, smooth, apex bifid and erose; rachilla 0.3–0.5 mm long, prolonged from the base of the floret (sometimes lacking in a small number of spikelets within the inflorescence), glabrous, smooth or scabrous. Calluses 0.1–0.2 mm long, slightly elongated, glabrous, smooth. Flowers; lodicules c. 0.5 mm long, lanceolate with acute apices, not lobed; anthers 3 in number, 0.7–1.1 mm long. Caryopses not seen. 2n= unknown.
Guatemala, endemic. Grows in alpine grasslands on volcanic soils, 2900–3700 m.
Guatemala. Huehuetenango: Sierra de los Cuchumatanes, alpine areas in vicinity of Tunima, 3400–3500 m alt., 7 July 1942, J.A. Steyermark 48321 (US1914763; US2208640); Sierra de los Cuchumatanes, between Tojiah and Chemal at km 319.5 on Ruta Nacional 9N, 3380 m alt., 31 July 1960, J.H. Beaman 3873 (US01247246); Sierra de los Cuchumatanes, between Tojquia and Caxin bluff, summit of Sierra de los Cuchumatanes, 3700 m alt., 6 Aug. 1942, J.A. Steyermark 50216 (US2181354). Solola: Woods 11 miles SE of Totonicapan, 3200 m alt., 27 June 1962, G.L. Webster 11826 (US3336153). Totonicapan: Desconsuelo, potrero natual, 3100 m alt., Aug. 1954, M. de Koninck 201 (US2153266); On the Tecum Uman Ridge at km 154 on Ruta Nacional No. 1, ca. 20km east of Totonicapan, 3340 m alt., 13 Aug. 1960, J.H. Beaman 4154 (US2381726).
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 (
Agrostis liebmannii (E. Fourn.) Hitchc., N. Amer. Fl. 17(7): 519. 1937. Apera liebmannii E. Fourn., Mexic. Pl. 2: 97. 1886.
Mexico. [Veracruz:] Orizaba, M. Botteri 93 in part (lectotype, designated here: P (P00740547 [image!]); isolectotypes: MSC fragm. ex P; epitype, designated here: Mexico. [Puebla:] Chinantla, May 1841, F.M. Liebmann s.n. “Plantae mexicanae Liebmann #12591” {handwritten on label} (US (US00595641!)). Syntype: Mexico. [Puebla:] Museum Botanicum Hauniense | Plantae mexicanae Liebmann | 1841–43 {printed label}, Gramineae N. 710 | Apera liebmannii Fourn. | [determ.] Fournier | Chinantla. May 1841, {handwritten on label} (NY (NY00345814 [image!]), US [not seen]).
Podagrostis liebmannii. A Whole plant B ligular area of flag leaf C section of inflorescence showing spikelets D floret, ventral view, with the rachilla prolongation indicated with a red arrow. Images of epitype specimen Liebmann s.n. (US00595641) courtesy of the United States National Herbarium (US).
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.
Mexico, endemic. The authors have only verified specimens from Hidalgo, Puebla and Veracruz states of central Mexico, with
Mexico. Hidalgo: Distrito Zacualtipan, pine woods and Sphagnum bogs about 3 miles from Zacualtipan on road to Tianguistengo, 2100 m alt., 4 July 1947, H.E. Moore, Jr. 3339 (US00486609).
Podagrostis liebmannii bears close affinity to P. thurberiana, a North American species that is found as far south as California (
Agrostis rosei Scribn. & Merr., Bull. Div. Agrostol., U.S.D.A. 24: 21, f. 5. 1901.
Mexico. Zacatecas: Sierra Madre mountains, [between Huasemote, Durango, and San Juan Capistrano], 18 Aug. 1897, J.N. Rose 2373 (holotype: US-301286 [not seen]; isotype: NY (NY00327649 [image!])).
Podagrostis rosei. A Whole plant B ligular area of upper culm leaf C section of inflorescence showing spikelets. D Floret, lateral view, with the rachilla prolongation indicated with a red arrow. A Digitized image of specimen P.M. Peterson 19503 (US00895358) courtesy of United States National Herbarium (US) B, C image of specimen P.M. Peterson 19124 (US00900682) D image of specimen J.R. Reeder 4662 (US00486613).
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. Calluses not or slightly elongated, 0.05–0.1 mm long, glabrous, smooth. Flowers; lodicules c. 0.4–0.5 mm long, lanceolate with acute apices, not lobed; anthers 3 in number, 0.8–1 mm long. Caryopses not seen. 2n = 14 (based on Reeder 4662).
Mexico, endemic. Ranges from Durango state in the north to Zacatecas in the south. Found in open forests at high elevations, 2600–2750 m alt. The authors have only verified specimens from Durango and Zacatecas states, with
Mexico. Durango: Pine forest with scattered oaks and occasional junipers, about 2 miles E of Puerto Buenos Aires, 9000 ft [2743 m alt.], 11 Oct. 1966, J.R. Reeder 4662 (US00486613); Sierra Madre Occidental, 0.5 miles SE of Los Charcos near small arroyo with Pinus cooperi, Juniperus and Panicum bulbosum, 23°0'57.5"N, 104°17'23.0"W, 2690 m alt., 21 Sep. 2005, P.M. Peterson 19053 (US00895358); Sierra Madre Occidental, 2.3 miles E of Los Mimbres along ridgetop with Pinus, Muhlenbergia and Quercus, 23°28'31.4"N, 104°55'3.6"W, 2630 m alt., 25 Sep. 2005, P.M. Peterson 19124 (US00900682).
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.
Aira trichodes (Kunth) Spreng., Syst. Veg. [Sprengel]) 1: 276. 1825[1824]. Agrostis trichodes (Kunth) Roem. & Schult., Systema Vegetabilium 2: 361. 1817. Vilfa trichodes Kunth, Nova Genera et Species Plantarum (quarto ed.) 1: 139. 1815[1816].
= Agrostis bogotensis Hack., Repert. Nov. Sp. Fedde 8: 518. 1910. Type: Colombia. S. Cristobal prope Bogota [près de Bogota], [2500–3000 m alt.], 13 July 1908, F. Apolliniaire s.n. (holotype: W (W19160027256 [image!]); isotypes: BM (BM000938528 [image!]), MPU (MPU027104 [image!]), SI (SI000495 [image!] fragm. ex US), US (US75365 fragm. [not seen])).
Peru. Crescit in crepidinibus Andium Peruvianum justa Montan, Santa Cruz et Guambos, alt. 1350 hexap. [2469 m alt.], floret Augusto, F.W.H.A. Humboldt & A.J.A. Bonpland s.n. (holotype: P [not seen]; isotypes: HAL (HAL0106929 [image!]), US (US75364! fragm. ex P)).
Podagrostis trichodes. A Whole plant B spikelets, with the floret detached and raised above the glumes so that the rachilla prolongation (indicated with a red arrow) can be seen C section of inflorescence D leaf blade, showing abaxial surface. A, B images of specimen L.E. Cuta-Alarcon 362 (FMB) C, D images of specimen M.C. Gomez 1 (US3534984).
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
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.
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
Colombia. Boyacá: Munic. Chiscas, Vereda Rechiniga, Páramo de la Mesa, área húmeda semiperturbada de Páramo, con Espeletia, Puya, Ageratina e Hypericum, 6.59515N, 72.44359W, 3741 m alt., 3 Mar. 2018, S.P. Sylvester 3091 (K, US, FMB); Munic. Chiscas, Páramo de Chacaritas, límites entre páramo y superpáramo, 6.62865N, 72.39440W, 4064 m alt., 4 Mar. 2018, S.P. Sylvester 3103 (K., US); Munic. Chiscas, Páramo el Peñon, borde de bosque de Polylepis, 6.60119N, 72.43715W, 3917 m alt., 5 Mar. 2018, S.P. Sylvester 3157 (K, US, FMB, COL, UPTC, SI); Munic. Duitama, Páramo de la Rusia, en la carretera que conduce a la Peña Negra, páramo con rocas expuestas, 5,58389N, 73,053263W, 3970 m alt., 21 Nov. 2017, M. Vorontsova 2218 (K, US, FMB, SI). Munic. Duitama, Páramo de la Rusia, vía que conduce a la Vereda Avendaños, 5.93247N, 73.0798W, 3726 m alt., 4 Oct. 2017, S.P. Sylvester 3038 (K, US, FMB, UPTC); Munic. Duitama, Páramo de Agueros, en la vía que conduce a la vereda Avendaños, Se observa evidencia de fuego y pastoreo, 5.91464N, 73.07114W, 3445W m alt., 28 Oct. 2017, S.P. Sylvester 3067ª (K, US, FMB); Munic. Mongua, Páramo de Oceta, Valle de Laguna Negra, vegetación de pajonal frailejonal con presencia de pastoreo de vacunos, 5.69525N, 72.79133W, 3694 m alt., 29 Nov. 2017, L.E. Cuta-Alarcón 354 (K, US, FMB). Santander: Paramo de la Angostura, Vereda El Mortino, 06°57'30"N, 72°43'30"W, 3605 m alt., 17 Nov. 2007, M.C. Gomez 1 (US-3534984). Santander Norte & Cesar: Limites entre Santander Norte y Cesar jurisdicciones, Cerro de Oroque, 3700–3900 m alt., 22–27 July 1974, H. Garcia-Barriga 20588 (US29665591; US2966621).
Venezuela. Mérida: Sierra Nevada, 9000 ft, 1847, Funck & Schlim 1630 (US); Sierra Nevada de Santo Domingo, between partaderos and Timotes, Paramo de Mucuchies, Pico Aguila, 4118 m alt., 21–26 Nov. 1959, H.G. Barclay 9685 (US3044346); Sierra Nevada de Santo Domingo, Paramo de Mucubaji, alrededores de la Laguna Grande, 3560–3600 m alt., 19 Nov. 1959, H.G. Barclay 9546 (US3096576); Sierra Nevada de Santo Domingo, Paramo Laguna de Mucubaji, carretera Barinas-Merida, 4200 m alt., 15 Nov. 1958, B. Trujillo 4072 (US3652663). Trujillo: Munic. Bocono, Laguna Eco to Pico Guarigay (summit), Monumento Natural Teta de Niquitao-Guirigay, summit of Pico Guarigay, 3600–3870 m alt., 16 Sep. 2003, B. Stergios 20450 (US00772686); Munic. Bocono, Laguna Larga, via Laguna Las Parias to Laguna Eco, Paramo de Motumbo, Monumento Natural Teta de Niquitao-Guirigay, 3400–3600 m alt., 15 Sep. 2003, B. Stergios 20420 (US00772685); Along the border with Merida state, 3400 m alt., 14 Sep. 2003, B. Stergios 20315 (US00772683); B. Stergios 20358 (US00772684); Monumento Natural Teta de Niquitao-Guirigay, sector Las Veguitas, 3060–3080 m alt., 20–21 Aug. 2002, L.J. Dorr 9157 (US00728039); Monumento Natural Teta de Niquitao-Guirigay, Paramo Guirigay, 3400–3600 m alt., 2–3 Aug. 2002, B. Stergios 19851 (US00728050).
The character of awn presence was not noted for this species by
Podagrostis trichodes closely resembles P. exserta and P. bacillata, considered endemic to alpine grasslands of Guatemala or páramos of Costa Rica and Panama, respectively (
Podagrostis bacillata can be differentiated from P. trichodes in having culms with at least one visible elongated internode and an exserted node (vs. usually without a visible elongated internode and exserted node in P. trichodes), panicles usually larger, 4–11 cm long (vs. 2.5–6 cm long in P. trichodes), panicle branches and pedicels generally smooth (vs. usually lightly to densely scabrous, infrequently smooth in P. trichodes), longer spikelets, 1.7–2 mm long (vs. 1–1.5 mm long in P. trichodes), glumes smooth apart from the lightly scaberulous keel (vs. glume keels often densely scabrous for most their length, with surfaces often scabrous distally in P. trichodes), lemmas smooth (vs. lightly to densely scabrous in P. trichodes), and rachilla prolongation 3–1.4 mm long (vs. 0.2–0.5 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.
This research was supported by a United Kingdom Department for Business, Energy and Industrial Strategy (BEIS) direct grant delivered via the Newton Fund and internal funding from Nanjing Forestry University. Marcus Lehnert and Natalia Tkach are thanked for providing images and details related to the HAL isotype of P. trichodes. Ingrid Lin is thanked for providing digitized specimen images. Maria Vorontsova helped initiate research in Colombia that allowed the conception of this study. Staff of the Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, are thanked for their assistance during visits by SPS and RJS. Many thanks go to Jeffery Saarela and Carmen Acedo for their helpful comments and edits that significantly improved the manuscript.