Bouteloua polymorpha (E. Fourn.) Columbus

Pentarrhaphis polymorpha (Fourn.) D. Grifl. Contr. U. S Nat. Herb. 14: 357. 1912.
Atheropogon polymorphus Fourn. Mex. PL Gram. 2: 141. 1886.
Pentarrhaphis Fournierana Hack. & Scribn. Bull. Torrey Club 17: 229. 1890. (Type from Guadalajara, Mexico, Pringle 2559 in 1889.)
Culms erect or someti,mes geniculate at the nodes, 10-40 cm. tall, the upper internodes elongate, the nodes ascendingvillous, otherwise glabrous; leaves mostly crowded toward the base; sheaths rounded on the back, glabrous, more or less villous at the throat; ligule ciliate, about 0.5 mm. long; blades firm, flat, 2-10 cm. long, 1 mm. wide, the culm blades much shorter than the basal ones, scabrous, especially on the margins, sparsely hirsute on both surfaces; spikes about 5 mm. long, villous, ascending or spreading; first glume 3-5 mm. long, scabrous, villous; second glume lanceolate, 3 mm. long, villous, the teeth short-aristate, the awn from between the teeth, 2-3 mm. long, scabrous; lemma 4-4.5 mm. long, cleft to the middle, the lateral lobes narrow, the central much broader, deeply toothed, very sparsely hispid, the awns of the lobes about 3 mm. long; palea as long as or slightly exceeding the lemma.
Type locality: San Luis de Potosi {Virlet 1395).
Distribution: Hills and plains, central Mexico.