1918] The Grasses of Illinois 413 



all spikelets narrow and produced into slender awns ; lemma of per- 

 fect spikelet 6 to 8 mm. long, awned. 



This species is usually a winter annual in Illinois and is becoming 

 increasingly abundant over nearly all parts of the state. It is spread- 

 ing rapidly along the railroad tracks and other waste places, growing 

 in soil in which other plants grow with difficulty. Among cultivated 

 crops it is easily controlled, as it is an annual and may be destroyed 

 by preventing the formation of seed. In pastures and along road- 

 sides its increase is alarming, as it drives out the better grasses. 



ILLINOIS SPECIMENS: Without locality, Vasey; Bear Creek, Mead, June, 

 1842. CHAMPAIGN CO. Urbana, Seymo^ir, May, 1880; Champaign, Mosher, May, 

 1914. Glover, Gates 1546. cook CO. Englewood, Dcrr, May, 1905. effingham 

 CO. Edgewood, Bartley, June, 1898. Henderson co. Oquawka, Patterson 778. 

 MARION CO. Without locality, Lapham in 1857; without locality, Bcbb in 18G0, 

 MENARD CO. Athens, Hall, June, 1864. peoria co. Peoria, McDonald, June, 

 1888; Peoria, Brendcl. piatt co. White Heath, Mosher, May, 1914. sr. clair 

 10. Mai-coutah, TFclsch. stark co. Wady Petra, F. H. Chase 588, 1441. ver- 

 milion CO. MuTieie, Mosher, May, 1914. wabash CO. Luc^s Prairie, Schncclc, 

 May, J 880; Mt. Carmcl, Schneck, June, 1879. will CO. Joliet, Ilill, June, 1907; 

 Joliet, SJccels, June, 1904. 



61. ELYMUS L. 



Wild Rye 



These grasses have dense terminal spikes, which arc usually slightly 

 nodding, and flat leaves. The spikelets are 2- to 6-flowercd and are 

 usually in pairs in alternate notches of the axis. The lemmas are 

 awned or awn-tipped. The glumes are usually narrow, sometimes 

 reduced to awns. The spikelets are placed flat against the stalk, and 

 both glumes are at the front of the spikelet. The species are all native. 



a. Glumes reduced to short, weak awns, the lemmas much longer. 



E. nivcrsifjlumis 

 aa. Glumes not reduced to awns, nearly or quite as long as the lemmas, 

 b. Lemmas awned. 



c. Glumes narrow, 1 mm. or less wide, spikelets usually covered with 

 long, fine hairs. E. striatus 



cc. Glumes always 2 mm. or more in width. 



d. Glumes strongly bowed out at the base, hardened and yellow for 



about 2 mm.; spikes usually included in the inflated upper 



sheaths. E. virginicus 



dd. Glumes not strongly bowed out at the bai^e, occasionally hardened 



and pale; spikes not included in the inflated upper sheaths. 



e. Glumes hardened at base; yellowish for 1 or 2 mm.; spikes 



stiff and erect. E. australis 



ee. Glumes not hardened at base and of the same color thruout; 



spikes nodding. E. canadensis 



bb. Lemmas awnless. E. arenarius 



Elymus arenarius L. 



Culms stout, 2 to 4 feet tall, from long, creeping rootstoeks; leaves 

 glabrous; blades involute at tip, the lower 8 to 12 inches long and 

 crowded at the base, the upper shorter ; spike stiff, 4 to 6 inches long, 



