GRAMINEAE (GRASS FAMILY) 51 



glumes broadly ovate, acute, nearly equal, smooth or scabrous on the keel; 

 lemma acuminate, the strongly scabrous midrib excurrent in a short point; 

 awn slender, 6 mm. long. Throughout our range. 



4. Oryzopsis asperifolia Michx. Fl. Bor. Am. 1: 51. 1803. Erect and slender, 

 with smooth or scabrous culms 25-50 cm. long, long rough flat evergreen leaves, 

 and narrow simple few-flowered panicles 6-10 cm. long: sheaths crowded at 

 the base; leaves 4-8 mm. wide: spikelets 6-8 mm. long: glumes glabrous, green, 

 the margins whitish; lemma whitish, sparingly pubescent; awn slightly twisted, 

 10-12 mm. long. Colorado and northward. 



19. ERIOCOMA Nutt. 



Densely tufted perennials with rigid culms, and contracted or open panicles. 

 Spikelets 1-flowered. Glumes membranous, broad; lemma firm, becoming 

 hard in fruit, broadly oval to elliptic, densely pubescent with silky hairs and 

 bearing a terminal readily deciduous awn; the callus at the base short and ob- 

 tuse. Stamens 3. Styles distinct; stigmas plumose. Grain free, inclosed in 

 the lemma. 



Panicle diffuse, the divisions filiform, flexuous and widely spreading . I.E. cuspidata. 

 Panicle more or less open, the branches erect or ascending . . . 2. E. caduca. 



1. Eriocoma cuspidata Nutt. Gen. 1: 40. 1818. Culms 3-6 dm. high: 

 leaves narrow, involute, smooth or somewhat scabrous: panicle dichotomously 

 branched, diffuse, 12-15 cm. long: spikelets 6-8 mm. long, on filiform and 

 flexuous pedicels: glumes pubescent, :! 5-nerved, broad and ventricose below, 

 attenuate-pointed; lemma about one half as loni: as the glumes, broadly oval, 

 densely pubescent with long silky erect hairs about one and a half times its 

 own length; awn 4-6 mm. long, readily falling off. INDIAN MILLET. Through- 

 out our range. 



2. Eriocoma caduca (Scribn.) Rydb. Mem. N. Y. Bot. Card. 1: 25. 1900. 

 Culms 3-5 dm. high: leaves n;im>\v, smooth or somewhat scabrous: panicle 

 more or less open; the branches erect or ascending, 5-15 cm. long: spikelets 

 5-6 mm. long: glumes scabrous or attenuate-pointed, 3-norved; lemma about 

 one half the length of the glumes, elliptic, densely clothed with silky hairs of 

 less than its own length; awn 7-9 mm. long, readily falling off. Infrequent; 

 northern Colorado and northward to Montana. 



20. MUHLENBERGIA Schreb. DROP-SEED. HAIR GRASS 



Perennials (rarely annuals) of greatly varying habit, with flat or involute 

 leaves, small spikelets, and narrow or open panicles. Rootstocks often scaly. 

 Spikelets 1-flowered, very rarely 2-flowered. Glumes 2, membranous or 

 hyaline, acute and sometimes awned; lemma 3-5-nerved, subtending a palet 

 and perfect flower and rarely an empty lemma, obtuse, acute, or very often 

 produced into a capillary awn; callus minute; palet 2-keeled. Stamens often 

 3. Styles distinct; stigmas plumose. Grain narrow, free, tightly inclosed in 

 the lemma. 



Panicle contracted, spike-like, the short branches rarely spreading. 

 Without scaly rootstocks. 



Awn 2-20 mm. long 1. M. gracilis. 



Awn less than 2 mm. long. 



Panicles 2-5 cm. long; second glume 3-nerved . . . . 2. M. filiculmis. 

 Panicle 5-9 cm. long; second glume 1-nerved . . . . 3. M. Wrightii. 

 With scaly rootstocks. 



Culms more or less branched . . 4. M. racemosa. 



Culms simple . . . . . . . . . . 5. M. comata. 



Panicle open, its branches long and spreading. 



Secondary branches of the panicle single; awn 2-4 mm. long . . 6. M. gracillima. 

 Secondary branches of the panicle fascicled; awn 1-2 mm. long . 7. M. pungens. 



1. Muhlenbergia gracilis Trin. Unifl. 193. 1824. Slender but rather rigid, 

 densely caespitose, 15-60 cm. high, with narrow involute leaves and con- 



