GRASS FAMILY 99 



divaricate; lowest flower of the spikelet sterile, like the empty glumes; lemma of 

 the second flower about 1 cm. long, trifid or entire; awn 5-7 cm. long. Moun- 

 tain sides: Colo. N.M. Submont. Subalp. Au. 



10. S. strigosum J. G. Smith. Stem 3-6 dm. high, glabrous or minutely 

 pubescent above; leaf-blades 1-2.5 dm. long, 3-6 mm. wide, flat, or the lower 

 involute, pilose; spike stout, exserted, 8-12 cm. long; empty glumes entire or 

 bifid, subulate-setaceous, 5-6 cm. long; lemma 8-10 mm. long, 3-cleft above, 

 the middle awn 5-7 cm. long, the lateral ones 1-2 mm. long. Valleys: Wash. 

 Ore. N.D. S.D. Submont. Je-Au. 



11. S. rigidum J. G. Smith. Stem 1-2 dm. high, glabrous; leaf-blades 

 3-8 cm. long, 2-3 mm. wide, rigid, involute, scabrous above; spike 2-8 cm. long, 

 exserted or included at the base; empty glumes 4, entire or two of them divided 

 to the base, awned, strongly divaricate, 2-3 cm. long; lowest floret usually ster- 

 ile; lemma 7-9 mm. long, trifid; awn stout, divaricate. Mountains: Calif. 

 Wash. Mont. N.M. Ariz. Subalp. Alp. Je-Au. 



12. S. glabrum J. G. Smith. Stem 3-6 dm. high, smooth and shining; 

 leaf-blades 7-15 cm. long, 2-5 mm. wide, flat, becoming involute; spike 5-8 cm. 

 long, sub-flexuose, the base usually enclosed in the uppermost sheath; empty 

 glumes bifid to near the base, the lobes subulate-setaceous, 6-8 cm. long; 

 lemma 7-8 mm. long, entire or minutely bifid. Hills: Calif. Wash. Wyo. 

 Utah. Subalp. Alp. My-Au. 



13. S. montanum J. G. Smith. Stem 2-4 dm. high, glabrous below, scab- 

 rous above; leaf-blades 5-10 cm. long, 3-4 mm. wide; spike erect, 5-10 cm. long; 

 empty glumes subulate-setaceous, some of the lower usually bifid, divergent, 

 5-6 cm. long; lemma 10-11 mm. long, 3-fid, 3-awned. Hillsides: Mont. Wyo. 

 Utah Ore. Submont. Mont. Je-Au. 



14. S. basalticola Piper. Stem 1-3 dm. high, smooth; leaf-blades 3-10 

 cm. long, 1-2 mm. wide, minutely scabrous on the nerves above; spike erect, 

 3-5 cm. long, barely exserted; empty glumes subulate, or some cleft to near the 

 base, spreading, 3-4 cm. long; lemma 8-10 mm. long, glabrous, glaucous, 3-fid; 

 middle awn 3-3.5 cm. long, divergent, scabrous, the lateral ones about 1 mm. 

 long. Basaltic soil and sandy slopes: Wash. Ida. Submont. Je. 



77. ELYMUS L. LYME-GRASS, WILD RYE, RYE-GRASS, BUFFALO RYE. 



Perennials, with rootstocks and cylindric spikes. Spikelets sessile, usually 

 2 or 3 at each node, but in some species mostly single, 2-several-flowered. 

 Empty glumes 2, inserted more or less obliquely, rigid, awn-like, subulate or 

 lance-linear, persistent, awn-pointed or awned. Lemma oblong or lanceolate, 

 rounded on the back, usually awned. Palet shorter than the glume, 2-keeled. 

 Stvles very short, distinct; stigmas plumose. 



Lemma long-awned. 



Spike broad; spikelets spreading. 



Empt> glumes lanceolate to lanceolate-subulate; spike dense. 



Empty glumes lanceolate, 5-7-nerved, thick and strongly curved at the base; 



spike erect. 

 Plant robust; spike scarcely exserted; lemma glabrous or nearly so. 



1. E. virginicus. 

 Plant slender; spike long-exserted ; lemma scabrous-hispid ulo us. 



2. E. jejunus. 

 Empty glumes narrowly linear-lanceolate, neither conspicuously thickened 



nor curved at the base; spike often nodding. 



Empty glumes usually minute, less than 15 mm. long. 4. E. diver stglurms. 

 Empty glumes 15-30 mm. long. 



Lemma hirsute or villous. 3. E. canaaensis. 



Lemma hispidulous-scabrous to glabrous. 



Robust; spike usually included at the base; leaf-blades 8-15 mm. 



wide 5. E. robustus. 



Slender; spike long-exserted; leaf-blades seldom more than 5 mm. 

 wide. 6. E. brachystachys. 



Empty glumes setaceous, hirsute; lemma hirsute; spike laxer. striatus 



Spike narrow; spikelets erect, appressed. 

 Lemma pubescent. 



Empty glumes lanceolate, 5-nerved. vuipinus. 



Empty glumes lance-subulate, indistinctly veined. 9. E. angustus. 



