Muhlenbergia laxa Hitchc.

Muhlenbergia laxa Hitchcock, sp. nov
Perennial; culms slender, branching, long-decumbent, spreading, lax, glabrous, manynoded, 40-70 cm. long; sheaths shorter than the internodes, glabrous; ligule thin, about 1 mm. long; blades flat, scaberulous, 2-5 cm. long, 1-2 mm. wide; panicles terminating the branches, green, narrow, compact, almost spikelike, interrupted, 4-6 cm. long, the spikelets clustered on short appressed branches, the axis flat, scaberulous, the branches and short pedicels pubescent; glumes about equal, pale with a green midnerve, oblong or somewhat spatulate, scabrous, more or less 2-lobed, awned from between the lobes, the body about 1.5 mm. long, the awn rather stout, scabrous, tapering from a flattish base to a fine point, about as long as the body; lemma glabrous below, scaberulous above, 3-nerved, about 2.5-3 ram. long, the lateral nerves excurrent as short awns, the mid-nerve extending into a slender scabrous awn 4-8 mm. long; palea a little shorter than the lemma, the keels short-awned.
Perennis; culmi laxi graciles longe decumbentes ramosi 40-70 cm. longi; laminae planae scaberulae 2-5 cm. longae 1-2 mm. latae; paniculae virides compactae interruptae 4-6 cm. longae, spiculis in ramulis brevibus acervatis; glumae aequales plus minusve bilobatae 1.5 mm. longae aristatae, arista circa 1 .5 mm. longa ; lemma infra glabrum, supra scaberulum, 3-nerviura, 2.5-3 mm. longum, nervis lateralibus excurrentibus, arista media 4-8 mm. longa.
Type collected in moist places, at Orizaba, Mexico, October, Botteri 1259 (U. S. Nat. Herb. no. 822840). The only other specimen seen is Botteri 1257 from the same locality.