258 MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



Figure 606.— Distribution of 

 Elymus canadensis. 



mas scabrous-hirsute to hirsute-pubescent, rarely glabrous, strongly 



nerved above, the awn divergently curved when dry, 2 to 3 cm 



long. % — River banks, open ground, and 

 sandy soil, Quebec to southern Alaska, south to 

 North Carolina, Missouri, Texas, Arizona, and 

 northern California (fig. 506). Elymus 

 canadensis var. robustus (Scribn. and 

 Smith) Mackenz. and Bush. Differing in the 

 stouter and denser only slightly nodding very 

 bristly spikes. Ql — Prairies, Massachusetts 

 to Montana, south to Kentucky, Missouri, 



Texas, and Arizona. Elymus canadensis var brachystachys 



(Scribn. and Ball) Farwell. Lemmas glabrous or' 



nearly so. 01 — Moist open or partly shaded 



ground, Arkansas, Oklahoma, Texas, and New 



Mexico. Grades into E. canadensis; many specimens 



of E. canadensis from Kansas to North Dakota 



have sparingly hirsute lemmas, showing a transition 



to this variety. 



20. Elymus riparius Wiegand. (Fig. 507.) Culms 



rather slender, erect, 1 to 1.5 m tall; sheaths glabrous; 



blades rather thin, flat, 5 to 15 mm wide, scabrous; 



spike somewhat nodding, 7 to 20 cm long; glumes 



narrow, about 1 mm wide at the middle, 2- to 4- 



nerved, somewhat indurate but scarcely bowed out 



at base ; lemmas minutely hispidulous to glabrous, 



the awn straight, mostly 2 to 3 cm long. % 



— River banks and low ground, Quebec and Maine 



to Michigan, south to North Carolina, Ohio, and 



Indiana; Arkansas (fig. 508) 

 E. virginicus var. glabriflorus in the nodding 

 spike and less indurate glumes; from E. cana- 

 densis in the straight awns and narrower and 

 somewhat more indurate glumes. When the 

 ranges of E. riparius and E. canadensis coincide 

 the latter may be distinguished by the hirsute- 

 pubescent lemmas. 



21. Elymus virginicus L. Virginia wild- 

 rye. (Fig. 509.) Culms tufted, erect, 60 to 



120 cm tall; sheaths glabrous; blades flat, 



scabrous, mostly 5 to 15 mm wide; spike usu- 

 ally erect, often partly included, 5 to 15 cm 



long; glumes strongly nerved, firm, indurate, 



yellowish, nerveless and bowed out at base 



leaving a rounded sinus, broadened above (1.5 



to 2 mm wide), scabrous, the apex somewhat 



curved, tapering into a straight awn, about as 



long as the body or shorter; lemmas glabrous 



and nerveless below, scabrous and nerved 



above, tapering into a straight awn usually 



about 1 cm long. % — Moist ground, low 



woods, and along streams, Newfoundland 



to Alberta, south to Florida and Arizona (fig. 510). Sometimes called 



Figure 507.— Elymus ri- 

 parius, X 1. (Wood- 

 ward, Conn.) 



Differing from 



Figure 508.— Distribution of 

 Elymus riparius. 



Figure 509.— Elymus virginicus, 

 X 1. (Hitchcock 79, Va.) 



