Calamagrostis orizabae (Rupr. ex E. Fourn.) Beal

Calamagrostis orizabae (Rupr.) Stcud.; Beal, Grasses N. Am
2:340. 1896.
Deyenxia orizabae Rupr.; Fourn. Mex. PI. Gram. 105. 1886.
Achaela plumosa Fourn. Mex. PI. Gram. 109. 1886. (Type from Mount Orizaba, Mexico.) Calamagrostis erecta Beal, Grasses N. Am. 2: 340. 1896. (Based on Achaela plumosa Fourn.) Calamagrostis plumosa Scribn.; Beal, Grasses N. Am. 2: 340, as synonym of C. erecta. 1896. (Based on Achaela plumosa Fourn.) Not Calamagrostis plumosa Spreng. 1825.
Culms in large tufts, erect, glabrous, or scaberulous below the panicle, 60-100 cm. tall; sheaths glabrous or scabrous; ligule narrow, about 3 mm. long; blades erect, slender, closely involute, scabrous or nearly glabrous, about half as long as the culm; panicle open, pyramidal, purple, 10-15 cm. long, the axis scaberulous, the branches slender, ascending or spreading, scaberulous, naked below, 4-8 cm. long, usually with a few short few-flowered branches intermixed; glumes acute, glabrous, about 4-5 mm. long; lemma minutely pubescent, 4-4.5 mm. long, awnless or with a short straight awn below the apex; callus-hairs very short; rachilla rather sparsely short-pilose, 1-2 mm. long.
Type locality: Mount Orizaba, Mexico (Galeotti 5780). Distribution: Mountains of southern Mexico.