Muhlenbergia rigens (Benth.) Hitchc.

Muhlenbergia rigens (Benth.) Hitchc. Jour. Wash Acad. Sci. 23:453. 1933.
Epicam pes rtgeyis Benth. Jour. Linn. Soc. 19: 88. 1881. (Based on Cinna macroura as described
by Thurber; S. Wats. Bot. Calif. 2: 276. 1880.) Crypsinna rigens Jones, Contr. West. Bot. 14: 8. 1912. (Based on Epicatnpes rigens Benth.)
Perennial; culms cespitose in small bunches, puberulent, scaberulous below the panicle, 1-1.5 meters tall, with 1 or 2 nodes near the base; sheaths glabrous or slightly rough, overlapping; ligule truncate, about 1-2 mm. long, somewhat auricled at the sides; blades scabrous, elongate, involute, tapering into a long slender point ; panicle grayish or pale, slender, spikelike, 15-30 cm. long or more; glumes 2-3 mm. long, from acute to obtuse or somewhat erose, scabrouspuberulent, rarely faintly 3-nerved; lemma slightly exceeding the glumes, scaberulous, sparsely pilose at base, 3-nerved toward the narrowed summit, awnless.
Type locality: California.
Distribution: Dry or open ground, hillsides, gullies, and open forest, Texas to southern California and northern Mexico.

Muhlenbergia leptoura (Piper) Hitchcock
Epicampes leptoura Piper, Proc. Biol. Soc. Wash. 18: 143. 1905.
Crypsinna setiglumis Jones, Contr. West. Hot. 14: 8. 1912. (Type from Garcia. Chihuahua, Jones in 1903.)
Perennial; culms comparatively slender, glabrous, scabrous below the panicle, 60-120 cm. tall, with 2-4 nodes; sheaths glabrous, longer than the internodes; ligule truncate, 2-3 mm. long; blades flat or usually involute, scabrous, elongate, attenuate to a long fine point, sometimes as much as 3 mm. wide near base ; panicle dense, spikelike, erect, pale, sometimes interrupted below, 10-25 cm. long, 5-6 mm. thick, the lower branches sometimes as much as 1 cm. long, the axis angled, scabrous; glumes lanceolate, rather thin, scabrous on the keel and slightly so on the back, 3-4 mm. long, extending into a short awn as much as 2 mm. long; lemma scabrous, rather broad, 3-nerved, awnless, 2-3 mm. long; palea broad, as long as or a little longer than the lemma.
Type locality: Colonia Garcia, Chihuahua (Townsend &• Barber 341). Distribution: Canyons and rocky beds of ravines. Chihuahua.