648 POACE^. 



to an empty glume. Empty glumes firm, narrowly linear, 1-3-5- 

 nerved, short- or long-awned, persistent, all those at one node 

 resembling an involucre, rarely the glumes split into many awns; 

 floral glume shorter, oblong or lanceolate, round on the back, 5- 

 nerved, obtuse or acute, awned or awuless; palea as long as the 

 lloral glume or shorter, 2-keeled. Stamens 3. St34es very short, 

 -distinct, stigmas feathery. Clrain oblong, hairy at the apex, grooved 

 on the inside, adhering to the palea. 



Perennial grasses, usually with broad flat or flrm convolute blades. 

 Spikes terminal, cylindrical, compact, often covered with many awns, 

 rachis breaking in pieces or not, densely or loosely many-flowered. 



Species 35-30, belonging to the temperate regions of Europe, 

 Asia, and Xorth America. 



Elymus is distinguished from Hordeum in having two or more 

 flowers to each spikelet, and is distributed into three sections : 



1. Sitanion Rafin. P oly anther yx Nees. Rachis articulate; 

 floral glume usually 3-awned. 



2. Clinelyna Griseb. Rachis continuous; spikelets usually 2 

 ■only at each notch, floral glume with one long awn. 



3. Psammelyna Griseb. Tall rigid species, often with more than 

 two spikelets to each notch ; floral glume unawned or with only 

 very short awnlike points. 



A. Spike soft, ciliate, awn short or none 1, 2, 3, 4 



B. Spike smooth or hirsute, awns none or very short. . 5, 6, 7 



C. Glumes awned (a) 



a. Some of the empty glumes divided 7, 8, 9 



a. Empty glumes not divided (b) 



b. Spike rigid, upright (c) 



c. Spike stout, partly included 10 



c. Spike narrow, exserted 11 



c. Spike stout, short, exserted 12 



b. Spike exserted, usually nodding (d) 



d. Spike large, 10-15 cm. long, floral glume often 

 fiexuose 13 



d. Spike more slender, awns more slender. . . 14 

 d. Spike dense, villous, awns straight 15 



