Agrostis cf. imberbis Phil. Anales Univ. Chile 94: 11. 1896

Sylvester, Steven P., Cuta-Alarcon, Lia E., Bravo-Pedraza, William J. & Soreng, Robert J., 2020, Agrostis and Podagrostis (Agrostidinae, Poaceae) from paramos of Boyaca, Colombia: synoptic taxonomy including a key to Colombian species, PhytoKeys 151, pp. 107-160 : 107

Agrostis cf. imberbis Phil. Anales Univ. Chile 94: 11. 1896 Fig. 6

= Agrostis stenophylla Phil., Anales Univ. Chile 94: 10. 1896. Type: Chile. Bío-Bío: Baños de Chillán, Jan. 1878, Philippi s.n. [ “146” in Herb. R. A. Phillippi s.d.; "No. 18 (II)" on SGO000000043 isotype] (holotype: SGO-PHIL (SGO-PHIL146); isotypes: BAA (BAA00000030 [image!]), BM (BM000938541 [image!]), SGO (SGO000000043 [image!], SGO000000061 [image!], SGO000000062 [image!]), US (US00156498! fragm. ex SGO-PHIL146), W (W19160040646 [image!])).

= Agrostis scotantha Phil., Anales Univ. Chile 94: 16. 1896. Type: Chile. Araucanía: La Cueva, Jan. 1887, C. Rahmer s.n. [ “183” in Herb. R. A. Phillippi s.d.] (holotype: SGO-PHIL (SGO-PHIL183); isotypes: BAA (BAA00000728 [image!] fragm. ex SGO-PHIL183, BAA00000729 [image!] fragm. ex B), SGO (SGO000000055 [image!], SGO000000056 [image!]), US (US00156493! fragm. ex SGO-PHIL183), W (W19160040640 [image!])).

= Agrostis moyanoi Speg. var. plicatifolia Speg., Anales Mus. Nac. Buenos Aires 7: 189. 1902. Type: Argentina. Chubut: Corcovado, Oct. 1901, N. Illin 2550 (holotype: LP (LP001364 [image!]; isotypes: BAA (BAA00000023 [image!])).

Type.

Chile. Ñuble: Valle de las Nieblas, Chillán, Jan. 1877, sin col. s.n. [ “185” in Herb. R. A. Phillippi s.d.] (holotype: SGO-PHIL (SGO-PHIL185); isotypes: BAA (BAA00001345 [image!]), BM (BM000938537 [image!]), SGO (SGO000000042 [image!], SGO000000044 [image!], US (US00156439! fragm. ex SGO-PHIL-185), W (W19160040633 [image!])).

Description.

Perennial herbs, laxly to densely tufted, sometimes stooling, with laterally tending or ascending pseudostolons, or rhizomatous with rhizomes ascending or vertical. Tillers intravaginal and extravaginal, with cataphylls usually present. Culms (7-)24-60(-65) cm tall, usually decumbent at their base or slightly creeping and rooting from the nodes, rarely completely erect, firm, with (0-)1-2 nodes exerted at flowering, smooth or scaberulous. Leaves usually mostly basal in first seasons growth, becoming mostly cauline as plant ages, glabrous, usually scaberulous with undeveloped scabers throughout, sometimes notably scabrous throughout; ligules 2.5-6.7(-10) mm long, of upper culm (2.8-)3-6.7(-10) mm long, usually scarious (at least in part), acute to acuminate, sometimes fimbriate, strongly decurrent with the sheath, abaxial surface scabrous; blades 2.8-9(-11) cm long, 0.5-1 mm wide in diameter as rolled or folded, convolute, involute, or conduplicate, rigid, abaxial surface smooth to scaberulous, adaxial surface lightly scabrous on the veins, apices usually naviculate-acute. Panicles (3-)6-12.5(-20) cm long, (0.5-)2-6 cm wide, open to slightly contracted when young, usually ovoid, slightly to greatly exerted from the basal foliage, lateral branches without spikelets near their base and for a long distance, long and ascending or spreading to becoming divaricate at maturity but not held close to the central inflorescence axis, central axis and panicle branches scaberulous; pedicels (0.9-)1.5-3.5 mm long, often slightly longer than their spikelets or sometimes shorter, dilated or not at their apex, scaberulous. Spikelets (2.3-)2.5-2.7(-3.5) mm long; glumes equal or subequal, similar or lower glume slightly wider and longer than the upper, 1-veined, keels usually scabrous in the distal ½-¾, upper glume sometimes completely smooth, apices acute to acuminate; floret usually 3/4 the length of the glumes or slightly longer; calluses glabrescent, with very sparse short hairs; lemmas 1.6-1.8(-2.5) mm long, glabrous, lightly scaberulous throughout or just in distal 1/2, sometimes with just undeveloped scabers as pustulate bases, 5-veined, apex obtuse or truncate, denticulate, muticous, mucronate, or sometimes with a short straight awn to 0.5 mm long, inserted in the middle or upper 1/3 of the lemma and not surpassing the glumes, weak and falling easily; paleas usually c. 0.2 mm long, < ¼ the length of the lemma; rachilla absent; anthers 1-1.2(-2) mm long.

Distribution and ecology.

Agrostis cf. imberbis is a new record for Colombia and páramo vegetation in general, and is not found in the most recent checklist for Colombia ( Giraldo-Cañas et al. 2016), the páramo checklist ( Luteyn 1999) or checklists for Ecuador ( Jørgensen and Ulloa-Ulloa 1994; Jørgensen and León-Yánez 1999), Venezuela ( Hokche et al. 2008; Bono 2010), or Costa Rica ( Morales-Quirós 2003) which host páramo vegetation. The species was previously considered to be restricted to Argentina and Chile ( Rúgolo de Agrasar 2012), but has also been recorded for Bolivia ( Jørgensen et al. 2014) and Peru ( Davidse et al. 1993; Soreng et al. 2003 and onwards; W3TROPICOS-Peru Checklist 2020; Óscar Tovar unpubl. data).

Additional specimens examined.

Colombia. Boyacá: Munic. Belén, Páramo de La Rusia, near Páramo El Consuelo, unprotected private land, somewhat disturbed páramo grazed by horses and rodents, dominated by Espeletia boyacensis [Cuatrec.], 6.02146N, 72.5718W, 3832 m alt., 22 Nov. 2017, M. Vorontsova 2228 (US); Munic. Chiscas, Páramo el Penon, Chiscas, borde de bosque de Polylepis , 6.59582N, 72.44284W, 3771 m alt., 5 Mar. 2018, S.P. Sylvester 3159 (K, SI, US); Munic. Chiscas, Páramo de Chacaritas, pajonal frailejonal, cercano al cerro de Chacaritas, con fuerte grado de inclinacion, 6.63108N, 72.39815W, 4082 m alt., 5 Mar. 2018, S.P. Sylvester 3144 (FMB, K, SI, UPTC, US); Munic. Duitama, Páramo de La Rusia, NW-N de Duitama, [5.9281N, 73.0936W], 3600 m alt., aislada, vertiente seca con Calamagrostis effusa [ Paramochloa effusa ] predominante, asociada con Espeletia boyacensis y Acaena cylindristachya , gramínea muy abundante, 7 Dec. 1972, A.M. Cleef 6821 (US2785719); Munic. Duitama, Páramo de La Rusia, vía que conduce a vereda de Avendanos, páramo semi-perturbado, pastado por cabras y quemado regularmente hasta hace 1 año, 5.95011N, 73.09097W, 3795 m alt., 1 Oct. 2017, S.P. Sylvester 3014 (COL, FMB, K, SI, US); 5.9324667N, 73.0798W, 3726 m alt., 4 Oct. 2017, S.P. Sylvester 3029 (FMB, US); S.P. Sylvester 3031 (K, US); [Munic. El Cocuy and Soatá,] between Soatá and Cocuy, Páramo del Alto del Escobal, [6.3514N, 72.5483W], 3750 m alt., 8 Oct 1938, J. Cuatrecasas 1232 (US1772922).

Notes.

Specimens studied from Boyacá match most characteristics of A. imberbis apart from sometimes the leaf blade abaxial surfaces being scaberulous, albeit with silica ‘pustules’ present throughout that sometimes developed into short hooks, and spikelets sometimes being shorter, to 2.3 mm long. Rúgolo de Agrasar (2012) mentions leaf blades can be smooth in A. imberbis under exceptional circumstances. Characters that are diagnostic for the species, such as narrow, rolled (convolute or involute) or conduplicate, rigid blades, long acuminate scarious ligules, usually large spikelets> 2.5 mm long, and glabrescent calluses, were all present on the specimens studied from Boyacá. Given its disjunct distribution and slight differences in morphology, coupled with knowledge that other widespread species such as A. perennans are actually numerous evolutionarily distinct taxa (Konstantin Romaschenko pers. communication), we refer to this species with ‘cf.’ to highlight that it needs to be checked in a molecular framework.

The species has a variable level of panicle congestion depending on the stage of maturity.

Similar species.

Agrostis subrepens , a species described from Mexico and whose presence in Colombia is uncertain (see notes on A. subrepens under 'Excluded species’ at the end of the taxonomic treatment), and A. cf. imberbis share similar morphologies. This includes the habit being decumbent and stooling, appearing rhizomatous or pseudostoloniferous, blades being convolute and rigid, and panicles usually large and open with spikelets that have a similar shape and size with lemmas lacking notable awns, ligules being strongly decurrent with the sheath and usually scarious (at least in part), and anthers> 1 mm long. While culm and panicle size are generally larger and anthers are often shorter in A. subrepens , some overlap occurs with A. imberbis , with ligule shape and size seeming to be the only solid character to differentiate them. Agrostis subrepens has shorter (<2.2 mm long), obtuse upper culm ligules while A. cf. imberbis has acute to acuminate upper culm ligules (2.8-)3-6.7(-10) mm long.

Agrostis perennans s.l. can sometimes have involute and rigid basal blades, but the upper culm blades are flat and lax, unlike those of A. cf. imberbis , which are rigid and convolute, involute, or strongly conduplicate throughout. The ligules in A. perennans s.l. are also usually shorter, with ligules of basal leaves and tillers 0.5-2.5 mm long, while those of A. cf. imberbis are> 2.5 mm long. Ligule apices of A. perennans s.l. are also truncate or obtuse-triangular, unlike the acute or long acuminate ligules of A. cf. imberbis .

Agrostis vinealis Schreb., a species not recorded for Colombia, but found introduced and naturalized in Argentina and Chile ( Soreng and Peterson 2003; Rúgolo de Agrasar 2012), bears similarities in terms of overall habit, being notably rhizomatous and having mainly basal leaves and an exerted open panicle that becomes congested after flowering, as well as other similarities such as the palea being reduced and awns sometimes absent (but usually with a persistent, geniculate and twisted, awn to 4 mm long, inserted near the base of the lemma). Agrostis vinealis usually has leaf blades that are flat towards the base, although sometimes these are involute and setaceous, and scabrous throughout or at least on the adaxial surface. It can also be differentiated by the ligules being often shorter, of the tillers 1-2.5 mm long, of the upper culms 1-4(-5) mm long, with apices rounded or bluntly pointed (vs. of the tillers> 2.5 mm long, of the upper culms (2.8-)3-6.7(-10) mm long, with apices acute to acuminate in A. cf. imberbis ).

Figures

Figure 6. Agrostis cf. imberbis A whole plant B flag ligule and portion of inflorescence C floret, lateral view D portion of inflorescence with close-up of spikelets. Images of Cleef 6821 (US 2785719), courtesy of United States National Herbarium (US).