550 
neutral, awnless; empty glumes aristiform about 1 cm. long, equaling the awn of 
the perfect floret. (H. pratense Huds.)—Rather low lands, mostly in alkaline soil, 
throughout the southern United States, 
3. H. pusillum Nutt. Annual: culms 3 to 5 din. high, slender, weak: spikes 3 to 
6 cm. long; lateral spikelets staminate or neutral, awnless; four anterior empty 
glumes broadened above the narrow stalk-like base, tapering above into a rigid 
awn about 1 em, long, equaling the awn of the perfect floret.—Central Texas to Cali- 
fornia, 
74. ELYMUS L. (LYMrE-GRass.) 
Spikelets 2 to 7-flowered, all perfect except the upper florets, com- 
pressed, sessile in clusters of 2 to 4 at each node in the spike: empty 
glumes nearly side by side in front of the spikelets 2 for each, thick- 
ened and nervose or aristiform; floral glume coriaceous or rigid, con- 
vex, very acute or awned, nearly equaled by the palet: grain linear, 
channelled, adhering to the palet and enveloping glume.—Rather 
coarse grasses with flat rough leaves. 
* Empty glumes thickened and nervose: spikes tardily disarticulating. 
1. B. Virginicus L. (VIRGINIA LYME-GRaAss.) Culms stout, about 1 dm. high: 
spikes rigidly erect, 1 to 1.5 dm. long: spikelets 2 to 4 at each node, rather closely 
appressed, nearly smooth throughout or hispidulous; empty glumes thickened, prom- 
inently 5 to 7-nerved, lanceolate, longer than the florets, bristle-pointed or short- 
awned; awn of floral glume usually straight and rigid, 2 cm. long or less.—River 
banks, central Texas and northward, Var. MINOR Vasey, of northern Texas, is 
smaller and slender (4 to 8 dm, high), with spikes loose, and the spikelets rather 
divergent. 
2. EB. Canadensis L. (CANADA LYME-GRAsS.) Culins stout, 5 to 10 dm. high: 
spike usually nodding, 1 to 2 dm. long: spikelets mostly in pairs, 3 to 5-flowered, 
hispid or pubescent throughout; empty glumes narrowly lanceolate, indistinetly 
3-nerved, tapering into a rather rigid awn 1 to 2 em. long and about one-half as long 
as the divergent awns of the 5-nerved floral glumes.—River banks, Texas and north- 
ward, Var. GLABRIFLORUS Vasey, of central Texas to Georgia, has smooth floral 
glumes and strongly 3-nerved empty glumes. 
** Empty glumes aristiform. 
+ Rachis persistent with the empty glumes, 
8. EB. striatus Willd. (DENNEr-GRAss.) Culms slender, about 1m. high: spikes 
usually nodding, 1 to 1.5 dm, long: spikelets 2 to 3 at each node; empty glumes about 
2 cm. long; floral glume sparsely hispid pubescent, terminating in an awn slightly 
exceeding the empty glumes.—Hillsides and open woods, central Texas and north- 
ward. Var. VILLOSUS Gray, of the same range, has sheaths and spikelets villous, 
+ + Spikes very readily disarticulating, 
4, B. elymoides (Raf.) Swezey. Culms 2 to 5 dm. high: leaves numerous, often 
involute: spikes 1 to 2 dm. long; empty glumes scabrous, spreading, 5 to 10 em, long, 
equaled by the awns of the floral glumes. (Sitanion elymoides Raf. Elymus Sitanion 
Schultes, )—Hills and dry mesas, central Texas to Minnesota and westward, 
75. HYSTRIX Meench. 
Spikelets 2 to 4-flowered, sessile, 2 or 3 together or solitary at the 
nodes of the flattened axis in a loose spike: empty glumes aristiform, 
