38 GEAMINEAE 



2. H. jubatum L. SQUIRREL TAIL GRASS. l-2 high, ascending : 

 spikes 2 / -4 / long, the awns widely spreading, so that it is l'-2' wide : 

 awns of flowering glume 8"-24" long : lateral flowers short-awned. In- 

 troduced locally in waste places. Very abundant at Sheffield. May- 

 June. 



54. ELYMUS L. WILD RYE. 



Spikelets all similar, one-seven-flowered in dense terminal spikes, ses- 

 sile, 2-4 at each joint of the rachis. Empty glumes two to each spikelet 

 forming a sort of involucre. Flowering glumes rounded on the back, 

 awned, 5-nerved. 



Empty glumes conspicuously thickened at base. 



Flowering glumes smooth. 1. E. Virginicus. 



Flowering glumes hispidulous-pubescent. 2. E. hirsutiglumis. 

 Empty glumes not conspicuously thickened at base. 



Empty glumes strongly hirsute. 3. E. striatus. 



Empty glumes not strongly hirsute. 4. E. Canademis. 



1. E. Virginicus L. Culms stout, glabrous, 2-4 high : spike 2 / -5 / 

 long, 5 x/ -7 /x wide (without awns), erect, from partly included in the 

 upper sheath to long-peduncled : spikelets 2-3-flowered, 2-3 together : 

 empty glumes strongly 5-7-nerved, bearing awns of their own length. 

 Common in woods and low grounds. June-October. 



2. E. hirsutiglumis Scribn. Resembles No. 1. Spike glaucous- whit- 

 ened : empty glumes rough : flowering glumes strongly hispidulous- 

 pubescent. Frequent on muddy river banks and in low woods. June- 

 October. 



3. E. striatus Willd. 2-4 high, slender : sheaths strongly pubescent: 

 spikes 2 x -5' long, 4 // -5 // wide (without awns), erect, long-exserted : 

 spikelets 1-2-flowered, mostly in pairs : empty glumes subulate, 3-nerved: 

 flowering glume 3 X/ long, bearing an awn 12 /x long. Common in dry 

 soil. 



4. E. Canadensis L. Culms stout, glabrous, 3-4 high : spike 3'-9' 

 long, 6 x/ -8 /x wide (without the awns), erect to drooping, exserted : 

 empty glumes rough, strongly several-nerved, 15 /x long with the awn ; 

 flowering glumes soft-pubescent, the awn SK'-IS" long. Occasional in 

 dry grounds. June-October. 



Var. robustus (S. & S. ) Mackenzie & Bush, n. comb. Spikes 9 X/ wide 

 (without awns), 5' -8' long: flowering glumes hispidulous-pubescent, the 

 awns often 24 /x long. Abundant in dry grounds. (Elymus robustus S. &S- ) 



Var. glaucifolius (Willd.) Gray. Whole plant strongly glaucous: 

 flowering glumes soft pubescent. Otherwise like var. robustus. Occa- 

 sional in dry grounds, throughout, especially abundant at Little Blue 

 Tank. 



55. HYSTRIX Moench. BOTTLE-BRUSH GRASS. 



Spikelets in terminal spikes, 2-3 together at each joint of the rachis, 

 2-3-flowered, on a short pedicel. Empty glumes awl-shaped, usually 



