Muhlenbergia subbiflora Hitchc.

Muhlenbergia subbiflora Hitchcock, sp. nov
Annual; culms slender, much-branched, spreading, glabrous, 30-50 cm. long; sheaths glabrous, somewhat keeled, mostly shorter than the internodes; ligule thin, acute, 3 mm. long; blades fiat, glabrous beneath, puberulous on upper surface, scabrous on the margins, mostly 3-7 cm. long, about 1 mm. wide; panicles 7-10 cm. long, the branches solitary or in pairs, 1-1.5 cm. distant, finally spreading or sometimes a little reflexed, 1-2 cm. long; spikelets on short pedicels or on short branchlets, somewhat crowded along the main branches, 1 -flowered or frequently 2-flowered, gray or plumbeous ; glumes subequal, acute, glabrous, about 2 mm. long ; first lemma narrowly lanceolate, terete or somewhat angled by the 3 rather prominent nerves, minutely pubescent along the lower part of the midnerve and margin, about 3 mm. long or a little less, awned ; awn 1-5 mm. long, straight or a little flexuous; palea a little shorter than the lemma, the bifid tip with 2 short slender awns.
Annua; culmi graciles ramosi 30-50 cm. longi; ligiila 3 mm. longa; laminae planae, subtus glabrae, supra puberulae, 3-7 cm. longae, 1 mm. latae; panicula 7-10 cm. longa, ramis patulis, 1-2 cm. longis; spiculae breviter pedicellatae I-2-florae plumbeae; glumae subaequales acutae glabrae 2 mm. longae; lemma 3 mm. longum prominente 3-nerviura, carina margineque inferiore pubescente, aristatum; arista 1-5 mm. longa, recta.
Tvpe collected on rich moist soil in garden, city of Durango, Mexico, November, 1896, Palmer 948 (U. S. Nat. Herb. no. 995434). The only other collection seen is Palmer 731, also from the vicinity of Durango.