Muhlenbergia plumbea (Trin.) Hitchc.

Muhlenbergia plumbea (Trin.) Hitchc. Contr. U. S. Nat Herb. 17: 296. 1913.
Vilfa plumbea Trin. M6m. Acad. St.-Petersb. VI. 6^: 98. 1840.
Sporobolus plumbeus Hemsl. Biol. Centr. Am. Bot. 3: 546. 1885. (Ba,sed on Vilfa plumbea Trin.) Sporobolus poaeoides Hack. Repert. Sp. Nov. 10: 167. 1911. (Type from Puebla, Mexico, Nicolas 5423.)
Perennial, with creeping rhizomes; culms loosely much branched at base, erect or spreading, usually from a decumbent base, glabrous, 10-40 cm. tall; sheaths glabrous, more or less compressed-keeled; ligule a ciliolate membrane less than 1 mm. long; blades flat or folded, scabrous on the margins, and on the upper surface toward the tip, mostly 5-10 cm. long, sometimes longer, 1-2 mm. wide; panicles terminal, erect, open, 3-15 cm. long, the few main branches solitary, rather distant, ascending or spreading, naked below, as much as 8 cm. long, the axis and branches scaberulous; spikelets plumbeous, about 3 mm. long, clustered at the ends of the branches on short appressed branchlets; glumes about half as long as the spikelet, equal, acutish, acute, or apiculate, glabrous; palea nearly as long as the lemma, obtuse.
Type locality: "Min. del Monte," Mexico.
Distribution: Open ground, pastures, alkaline meadows and along ditches, states of Mexico and Puebla.