38 GKAMINEAE 



2. H. jubatum L. Squirrel Tail Grass. 1°-2° high, ascending : 

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

 awns of flowering glume 8'''-24''^ long : lateral flowene short-awned. — In- 

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

 June. 



54. ELYMUS L. Wild Rye. 



Spikeletsall similar, one-seveu-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 hack, 

 awned, 5-nerved. 



Empty glumes conspicuously thickened at base. 



Flowering glumes smooth. 1. E. Virginicus. 



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

 Empty glumes not conspicuously thickened at base. 



Empty glumes strongly hirsute. 3. E. strinfiis. 



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



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

 long, 5^^-7^^ 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^-5' long, 4^^-5^^ wide (without awns), erect, long-exserted : 

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

 flowering glume 3'^ long, bearing an awn 12^^ long — Common in dry 

 soil. 



4. E. CanadeiLsis L. Culms .stout, glabrous, 3°-4° high : spike 3^-9^ 

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

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

 flowering glumes soft-pubescent, the awn 9''-15'^ long.— Occasional in 

 dry grounds. June-October. 



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

 (without awns), .''/-8^ long: flowering glumes hispidulous-pubescent, the 

 awns often 21^' long. — Abundant in dry grounds ( Ely inns rolnistu.s S. & S. ) 



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



flowering glumes soft pubescent. Otherwise like var. robustus. — i.)cca- 



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 shoit pedicel. Empty glumes awl-shaped, usually 



