Agrostis capillaris L., Sp. Pl. 1: 62. 1753

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 capillaris L., Sp. Pl. 1: 62. 1753 Fig. 4

Agrostis polymorpha var. capillaris (L.) Huds., Fl. Angl. 1: 31. 1778.

Trichodium capillaris (L.) Roth, Nov. Pl. Sp. 41. 1821.

= Agrostis tenuis Sibth., Fl. Oxon. 36. 1794. Agrostis capillaris Huds., Fl. Angl.: 27. 1762, hom. illeg., non L., 1753. Type: England (not located). Many other heterotypic synonyms.

Type.

[Habitat in Europae pratis], Herb. A. van Royen s.n. (lectotype, designated by Widén 1971: 65: L (L0052645 left-hand specimen [image!]); isolectotype: L).

Description.

Perennial herbs, loosely to densely tufted with short to extensive rhizomes and sometimes with well-developed stolons. Tillers extravaginal, with cataphylls present. Culms 10-80 cm tall, erect or decumbent at their base, delicate, usually with 2-5 nodes exerted at flowering, smooth or scaberulous. Leaves basal and cauline, glabrous, smooth or scaberulous; ligules 0.2-1.5(-2.9) mm long, of basal leaves and tillers ≤ 1 mm long, distinctly shorter than wide, of culm leaves 0.5-1.5(-2.9) mm long, membranous, rounded to truncate, not or only slightly decurrent with the sheath, abaxial surface scaberulous to sometimes smooth; blades 1-17 cm long, (0.6-)1-5 mm wide as opened out, basal blades and those of tillers often involute and 0.3-0.8 mm wide as rolled, sometimes flat, culm blades generally flat or becoming convolute upon drying, less often involute, usually soft and lax, rarely firm, abaxial and adaxial surfaces and margins smooth or scaberulous. Panicles 3-20 cm long, 2.5-8 cm wide, usually open, sometimes partially closed after flowering, lax, usually ovoid to pyramidal, subincluded in the basal foliage to greatly exerted, lateral branches without spikelets in the lower ½, long, ascending or spreading but not held close to the central inflorescence axis, central axis and panicle branches scabrous or smooth; pedicels 1-2 mm long, usually shorter than their spikelets, dilated or not at their apex, smooth or scaberulous. Spikelets (not including awn, if present) (1.8-)2-2.5(-2.7) mm long; glumes subequal, the lower slightly longer than the upper, 1-veined, lower glume keel usually scabrous in the distal half, sometimes scabrous throughout, upper glume keel often smooth throughout, infrequently scabrous in the distal half, apices acute; floret 2/3-3/4 the length of the glumes; calluses glabrous or with 2 sparse lateral tufts of short hairs; lemmas 1.4-2.2 mm long, 3- or 5-veined, glabrous or sometimes pubescent at the base when 5-veined, smooth, apex obtuse or truncate, erose, muticous or with an awn 0.5-3 mm long, inserted above the middle of the dorsal keel, exerted from the glumes or not, straight, flexuose or geniculate, twisted or not, weak and easily falling, usually found only on the 5-veined lemmas; paleas 0.6-1.3 mm long, (2/5-) ½-¾ the length of the lemma; rachilla absent; anthers 0.8-1.4 mm long.

Distribution and ecology.

Eurasian, introduced to the north of South America. Predominantly found in grazed páramo and puna vegetation. Agrostis capillaris is here recorded as a new regional record for the Depto. Boyacá of Colombia. Giraldo-Cañas et al. (2016) mention it as an introduced and cultivated herb based on the record of A. tenuis by Hafliger and Scholz (1981). It is likely to be an under-recorded element in many Colombian regions with páramo habitat.

Other specimen examined.

Colombia. Boyacá: Munic. Duitama, Páramo de la Rusia, vía que conduce a vereda de Avendaños, 5.9324667N, 73.0798W, 3726 m alt., 4 Oct. 2017, S.P. Sylvester 3021 (COL, FMB, K, SI, UPTC, US).

Notes.

A highly variable species comprising a set of ecologically and genetically distinct populations that are difficult to pull apart taxonomically. The species can hybridize with A. gigantea ( A. x bjoerkmannii Widen), A. stolonifera ( A. x murbeckii Fouill. ex P.Fourn.), A. vinealis Schreb. ( A. x sanionis Asch. & Graebn.), etc., with hybrids exhibiting intermediate characteristics and all being sterile ( Cope and Gray 2009). Agrostis capillaris is often planted in the Neotropics as part of a lawn mix with other species, or for livestock feed.

Similar species.

Agrostis castellana Boiss. & Reut., which has not been recorded for Colombia but is found introduced and naturalized further south in Argentina and Chile ( Rúgolo de Agrasar 2012). The only certain characters for distinguishing A. castellana from A. capillaris are that, in A. castellana , the terminal spikelets of the inflorescence branches have a distinctly pubescent upper dorsal surface of the lemma, at least towards the margins, while they are usually glabrous or pubescent only at the base in A. capillaris . The panicles are also contracted, lanceolate to narrowly oblong after flowering in A. castellana , while being open with spreading branches after flowering in A. capillaris . Other characters, such as awn presence, are too variable to be useful in separating these species. Furthermore, these species can also hybridize to produce A. x foilladei P. Fourn., which has been reported from seed mixtures for amenity grassland in the UK ( Cope and Gray 2009). Agrostis gigantea , another closely related species which can usually be readily distinguished by its greater size and relatively longer ligules, does have some smaller variants with thinner leaves that superficially resemble A. capillaris , but the ligule will always settle the identity.

Figures

Figure 4. Agrostis capillaris A spikelet, lateral view, with floret detached and raised above the glumes B Whole plant. Images of Sylvester 3021 (FMB).