Agrostis L. Sp. Pl. 1: 61. 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 L. Sp. Pl. 1: 61. 1753

= Vilfa Adans., Fam. Pl. 2: 495. 1763. Type: Vilfa stolonifera (L.) P. Beauv. (lectotype, designated by Hitchcock 1920: 127).

= Trichodium Michx., Fl. Bor.-Amer. (Michaux) 1: 41. 1803. Type: Trichodium laxiflorum Michx. (lectotype, designated by Hitchcock 1920: 127). Many other heterotypic synonyms.

Type.

Agrostis stolonifera L. (lectotype, designated by Hitchcock 1920: 125)

Description.

Annuals or perennials. Leaves basal or cauline; ligules membranous to scarious. Inflorescence a panicle, lax and open to contracted and spikelike. Spikelets 1-flowered, disarticulating above the glumes, laterally compressed; glumes as long as the spikelet, equal or subequal, persisting on the plant after the florets have fallen, usually 1-veined, rarely 3-veined; floret usually notably shorter than the glumes or reaching to ¾ the length of the glumes, exceptionally longer; lemmas membranaceous or hyaline, generally thinner than the glumes, dorsally rounded, 3- or 5-veined, veins not or distinctly evident; paleas often absent or noticeably shorter than the lemma, sometimes reaching to ¾ the length of the lemma, hyaline and slightly to notably thinner than the lemmas, keels usually obscure, rarely distinct, glabrous, usually smooth, rarely scaberulous; calluses rounded, glabrous or pubescent and usually with 2 lateral tufts of short hairs; rachilla prolongation absent. Flowers perfect; anthers 3 in number, 0.3-1.8 mm long. Caryopses hard (in species from Colombia) or sometimes with liquid endosperm.

Notes.

In Colombian páramos, taxa of Agrostis can be most easily confused with those of Calamagrostis s.l. (i.e., Cinnagrostis Griseb., Deschampsia P. Beauv., Paramochloa P.M. Peterson, Soreng, Romasch. & Barberá, Peyritschia E. Fourn.; Peterson et al. 2019; Sylvester et al. 2019a), Podagrostis , Polypogon Desf., and Sporobolus R. Br. The genera previously circumscribed as Calamagrostis s.l. ( Peterson et al. 2019; Sylvester et al. 2019a) can usually be differentiated by a combination of a prolonged hairy rachilla emerging from the base of the floret, a well-developed palea, a hairy callus, an awn present and inserted dorsally on the lemma, and an upper glume with well-developed lateral veins, although certain species are missing some of these characteristics (see Sylvester et al. 2019a). Polypogon is principally differentiated by spikelets that disarticulate below the glumes, with the grain, lemma, palea, glumes and part of the pedicel falling together. The glumes are also often awned in Polypogon . Sporobolus is principally differentiated by its ligule in the form of a line of hairs, its well-developed paleas with the same consistency as the lemma, and the lemmas being 1(-3) veined.