MANUAL OF THE GRASSES OF THE UNITED STATES 249 



awned from the tip. Erect, usually rather tall perennials (one annual), with 

 flat or rarely convolute blades and slender or bristly spikes, the spikelets 

 usually crowded, sometimes somewhat distant. Type species, Elymus sibiricus 

 L. Name from Elumos, an old Greek name for a kind of grain. The species in 

 which the spikelets are mostly solitary can be distinguished from Agropyron 

 by the narrow or subulate glumes. The seed of certain species (e.g., E. mollis 

 and E. canadensis) have been used for food by the Indians. 



The species of Elymus are for the most part good forage grasses and in 

 some localities form a part of the native hay. In the wooded areas of the 

 Northwest, E. glaucus is one of the valuable secondary grasses of the ranges. 

 The species with creeping rhizomes are likely to be of value as soil or sand 

 binders. E. mollis is a natural sea-dune grass, and E. arenicola and E. flavescens 

 are common on inland shifting dunes. E. triticoides is to be recommended for 

 holding embankments. On the western ranges E. cinereus and E. triticoides 

 are important. 



la. Plants annual ; spike long-awned, nearly as broad as long 1. E. caput-medusae. 



lb. Plants perennial; spike much longer than broad. 

 2a. Rhizomes present, slender, creeping. 



Glumes lanceolate, awnless or awn-pointed. Plants of coastal dunes. 



Glumes and lemmas papery, distinctly nerved 2. E. mollis. 



Glumes and lemmas firm, faintly nerved (lemmas nerved at apex). 



3. E. VANCOUVERENSIS. 



Glumes subulate or very narrow. 

 Spikelets glabrous. 



Lemmas acute or awn-pointed, brownish or tan-colored; spikelets paired or soli- 

 tary, crowded. 

 Spikelets usually in pairs, or paired and solitary in a single spike; culms 60 to 



120 cm. tall — . 8. E. triticoides. 



Spikelets solitary in short spikes; culms 10 to 20 cm. tall 9. E. pacificus. 



Lemmas awned, the awns 3 to 14 mm. long; spikelets usually solitary, rather 



distant, pale 10. E. simplex. 



Spikelets densely villous to coarsely, sometimes sparsely, pubescent. 

 Lemmas awned or awn-tipped; spike 5 to 15 cm. long. 



Lemmas copiously villous; awn 1 to 4 mm. long _ 6. E. innovatus. 



Lemmas hirsute or hirtellous; awn 5 to 10 mm. long 7. E. hirtiflorus. 



Lemmas awnless; spike 10 to 25 cm. long. 



Glumes pubescent; lemmas soft, densely villous 4. E. flavescens. 



Glumes glabrous or nearly so; lemmas relatively firm, coarsely pubescent, some- 

 times sparsely so 5. E. arenicola. 



Lemmas glabrous to sparsely strigose; culms glabrous; spikes usually com- 

 pound; blades 15 to 35 mm. wide 13. E. condensatus. 



Lemmas more or less pubescent; culms harsh-puberulent, at least about the 

 nodes; spikes not or scarcely compound; blades 5 to 15 mm. wide. 



14. E. cinereus. 

 2b. Rhizomes wanting (or short and stout in E. condensatus). Plants tufted. 

 3a. Rachis tardily disjointing; glumes and lemmas awned. 



Spike mostly 5 to 7 mm. wide; spikelets mostly in twos; blades subinvolute. 



18. E. macounii. 

 Spike 8 to 10 mm. wide; spikelets often in threes; blades flat, 5 to 10 mm. wide. 



19. E. aristatus. 

 3b. Rachis continuous. 

 4a. Glumes subulate to subsetaceous, not broadened above the base, the nerves 

 obscure except in E. villosus. 

 Lemmas awnless or awn-tipped, the awn shorter than the body. 



Spike thick, sometimes compound; spikelets commonly in twos to fours. 



Lemmas glabrous to sparsely strigose ; culms glabrous ; spikes usually com- 

 pound; blades 15 to 35 mm. wide 13. E. condensatus. 



Lemmas more or less pubescent; culms harsh-puberulent at least about the 

 nodes; spikes not or scarcely compound; blades 5 to 15 mm. wide. 



14. E. cinereus. 

 Spike slender; some or most of the spikelets solitary at the nodes, the paired 

 spikelets near the middle. 



