Muhlenbergia nigra Hitchc.

Muhlenbergia nigra Hitchcock, sp. nov
Perennial ; culms densely cespitose in large clumps, puberulent below, scabrous below the panicle, 2or 3-noded, 0.5-1.5 meters tall; sheaths scaberulous or the lower glabrous; ligule truncate, mostly 1-2 cm. long, much broader than the base of the blade, decurrent on the margins of the sheath ; blades mostly slender, closely involute, the wider ones sometimes flat, about 2 mm. wide, deeply sulcate and scabrous on the upper surface, scaberulous beneath especially toward the involute attenuate point, the base of the closely involute blades usually with a curve, becoming in the old leaves a strong semicircular bend; panicle dense, spikelike, erect, tapering a little at each end, dark green or olive, 5-15 cm. long, 8-10 mm. wide, the axis scabrous, strongly sulcate, the short branches scabrous, closely set on the axis, bearing 1-3 spikelets, the pedicels scabrous-pubescent; glumes 6-10 mm. long, narrow, very scabrous, acuminate, more or less awn-pointed; lemma resembling the glumes but somewhat shorter, 3-nerved.
Perennis; culmi dense caespitosi erecti 0.5-1.5 m. alti; ligula 1-2 cm. longa; laminae involutae; panicula densa nigricans 5-15 cm. longa 8-10 mm. lata; glumae angustae dense scabrae acuminatae 6-10 mm. longae; lemma glumis simile sed paullo brevius.
Tvpe collected on cool slopes under pines, alt. about 3300 m.. Nevada de Toluca. Mexico, September 2. 1892, Pringle 4211 iV . S. Nat. Herb. no. T46689).
Distribution: Southern Mexico, from Veracruz to Toluca; Guatemala (Volcano Agita).