GRASSES OF IOWA. 841 



B. Spikes more or less nodding; empty glumes not thickened or curved at 

 base, mostly scabrous: awns 2-5 mm. long. 



1. Culms slender; spikes slender; empty glumes subulate, 1-3-nerved; 



flowering glumes 6-9 mm. long. 



a. Spikes very narrow, 5-6 mm. wide or, including the awns, 1 



cm. wide; spikelets solitary or in pairs, appressed; awns 1 

 cm . long or less E. Macounii.* . 



b. Spikes wider, 9-10 mm. wide or, including the awns, 2-2.5 cm. 



wide; spikelets in pairs, divergent from the rachis; awns 

 1.5-3 cm long. 



(1) Spikelets glabrous E. Arkansanus :' . 



(2) Spikelets hirsute E. striatus. 6 . 



(a) Spike broader, heavier and with more hirsute empty 



glumes E . striatus var. Ballii.' . 



(b) Glumes hairy and having a villous sheath. 



— E. striatus var . villosus.*. 



2. Culms stout; spikes stout; empty glumes narrowly lanceolate, 3-7- 



nerved, (or subulate in E. robustus); flowering glumes 10-14 

 mm. long. 



a. Culm 3-9 dm. high; spike short, dense; flowering glume smooth, 



scabrous E. brachystachys . 9 . 



b. Culms mostly taller; spike longer, often loose and interrupted; 



flowering glumes mostly hirsute E . Canadensis .'" . 



c. Spike very densely flowered, compact, often included at base; 



empty glumes narrow, 1-3-nerved, very scabrous; flower- 

 ing glumes scabrous-hirsute; awn longer E. robustus". 



1. ELYMUS VIRGINICUS. 



Elymus Virginicus L . Sp. PI. 84. 1753. Watson and Coulter. Gray. 

 Man. Bot. 673. pi. 11. 1890. (6 ed.) Scribner. Grasses of Tenn. Bull. 

 Univ. Tenn. Agrl. Exp. Sta. 7: 126. /. 182. 1894. Beal. Grasses of N. A. 

 2: 653. 1896. Nash in Britton and Brown. 111. Fl. 1: 230. /. 534. 1896. 

 Scribner. Bull. U. S. Dept. Agrl. Div. Agros. 17: 316. f. 612. 1900. 



DESCRIPTION. 



Terrell Grass. An erect, smooth grass, 2 to 3 feet (5-7 dm.) 

 high, with rigid, terminal spikes which are often partly included in the 

 upper leaf sheath. Sheaths striate, smooth or hairy; ligule short; leaf 

 blade 6 to 12 inches (1-2-3 dm.) long, 2 to 4 lines (4-8 mm.) wide; 

 acute, scabrous. 



Spikes 3 to 5 inches (.6-1 dm.) long, the rachis smooth or scabrous. 

 Spikelets two to three-flowered, smooth ; empty glumes lanceolate, thick 

 and rigid, strongly nerved, awn-pointed; flowering glumes lanceolate, 

 rounded on the back, awned. Moist soil, borders of thickets and open 

 woodlands. June to September. See figure 240, on page 339. 



