549 
71. LOLIUM Ef. 
Spikelets 5 to 10-flowered, perfect, compressed with the edge to the 
axis, sessile, and alternately 2-ranked in long rigid terminal spikes: 
upper empty glume external, rigid, 5 to 7-nerved; lower empty glume 
wanting except in the terminal spikelet; floral glume coriaceous, 3 to 
d-nerved, obtuse or subacute, short-awned or awnless, convex, 
smooth, nearly equaled by the palet and large adherent grain.—Coarse 
erect grasses with numerous flat leaves. 
1, L. perenne L. (PERENNIAL RYE GRASS.) Culms 4 to 8 dm. high: root peren- 
nial: spikelets 1 to 2 cm. long, exceeding the intervals; empty glume about equaling 
the adjacent floret.—Introduced, sometimes cultivated. 
2, L.temulentum L. (DarNnevt.) Culms rather stout, 5 to 10 dm. high: spike- 
lets 1 to 2 cm. long, often shorter than the intervals; empty glumes usually exceed- 
ing the spikelet; florets short, obtuse.—Introduced. 
72. AGROPYRON Guertn. 
Spikelets 4 to 15-flowered, perfect, compressed, sessile, with the side 
against the axis, usually solitary, alternately 2-ranked in the terminal 
spike: empty glumes subequal, herbaceous, acute, 5 to 7-nerved; floral 
glume rather rigid, herbaceous, acute or bristle-pointed, 5 to 7-nerved, 
exceeding the prominently keeled palet: grain linear with a broad 
channel.—Rather coarse erect grasses. 
1. A. repens, var. GLAUCUM (Desf.) Scribn. (COLORADO BLUE-STEM.) Culms 4 to 
10 dm. high, from running rootstocks, usually glaucous throughout: leaves narrow, 
rather rigid, sometimes involute: spike 1 to 2 dm. long, with one or sometimes two 
or three spikelets at the nodes: spikelets 1 to 2 em, long, 5 to 15-flowered, awnless. 
(Triticum glaucum Desf. Agropyrum glaucum R. & S.)\—High plains, western Texas 
and northward. 
73. HORDEUM Fourn. (BARLEY.) 
Spikelets I-flowered with an awlshaped rudiment next to the palet, 
nearly sessile, 3 at each node of the axis, forming dense spikes: empty 
glumes somewhat stalked, in pairs in front of, each spikelet, 6 in num- 
ber, forming a kind of involucre, slender, awn pointed or aristiform: 
lateral florets staminate or neutral, or reduced to bristles; middle floret 
perfect; floral glume convex, rigid, herbaceous, tapering into an awn, 
hispid or smooth; palet equaling the glume: grain oblong, usually 
adherent.—Rather low annual or biennial grasses with numerous 
rather short flat leaves; the close bristly spikes disarticulating at 
maturity. 
* Spikes bushy, with spreading awns 8 to 8 em. long. 
1. H. jubatum L. (SquirreLt TAIL.) Culms 2 to5 dm. high: spike 1 dm. long 
or less, light green or yellow, very fragile; lateral florets reduced to awns slightly 
exceeding the perfect floret; empty glumes aristiform, slightly exceeded by the awn 
of the perfect floret.—Prairies, Texas to Minnesota and westward. A very trouble- 
some weed. 
* * Spikes narrow, with rigid nearly erect awns 2? om. long or less. 
2. H. nodosum L. (WILD BARLEY.) Perennial (2), culms 4 to 8 dm. high: spike 
narrow, 4 to 8 din. long, usually dark green or purple; lateral spikelets staminate or 
11874—No. 3 14 
