98 POACEAE 



Empty glumes setaceous, or cleft to near the base into setaceous divisions. 

 Sheaths and blades more or less long-pubescent. 



Lemma glabrous. 9. S. moUr. 



Lemma scabrous. 10. S. sirigosum. 



Sheaths and blades glabrous, scabrous, or puberulent; lemma smooth 

 below, scabrous above. 

 Awns of the lemma 3—4 cm. long, divergent; plant very low. 



11. S. rigidum. 

 Awns of the lemriia 4-7 cm. long; plant taller, more than 2 dm. high. 

 Leaf-blades 2-5 mm. broad, flat or slightly involute. 



Plant perfectly glabrous; awn ascending. 12. S. glabrum. 



Plant puberulent or scabrous; awns divergent. 



13. S. monlanum. 

 Leaf-blades 1-2 mm. broad, strongly involute. 



14. S. basallicola. 



1. S. lanceolatum J. G. Smith. Stem 3-5 dm. high, erect, smooth; leaf- 

 blades 8-15 cm. long, 2-3 mm. wide, rigid; spikes erect, 6-10 cm. long, barelj' 

 exserted; empty glumes 5-6 mm. long, usually 2-nerved, entire or unequally 

 2-cleft, the longer awn scabrous, divergent, 1-1.5 cm. long; lemma 8-9 mm. 

 long, glaucous, entire or minutely 3-cleft; awns spreading, 2-5 cm. long. Agro- 

 pyron sitnnioides J. G. Smith. Mountains: Mont. — S.D. Suhmont. Au. 



2. S. marginatum Scribn. & Merrill. Stem 2-3 dm. high; leaf-blades 3-9 

 cm. long; spike 3-6 cm. long; empty glumes 5 mm. long, entire; awn spreading, 

 about 1.5 cm. long; lemma glabrous, about 7 mm. long; awn like those of the 

 empty glumes. Bare mountain slopes: Wyo. Subalp. Jl. 



3. S. pubiflorum J. G. Smith. Stem erect, 2-3 dm. high, strigose above; 

 leaf-blades puberulent beneath, scabrous above, 2-10 cm. long, spreading; spike 

 exserted, 5 cm. long; empty glumes 4-6 cm. long; lemma of the lowest flower 

 7 mm. long, scabrous and finely pubescent; awn scabrous, straight, ascending, 

 5-6 cm. long. Dry hills: Colo^— N.M.— Ariz. Son. Ap-Je. 



4. S. elymoides Raf. Stem 3-6 dm. high, glabrous and glaucous; leaf- 

 blades smooth and glaucous or puberulent, 1-2 dm. long, 2-4 mm. wide, flat or 

 involute; spike somewhat nodding, exserted or enclosed at the base in the upper- 

 most sheath; empty ghimes 6-8 cm. long; lemma 8-11 mm. long; awn scabrous, 

 spreading, 5-6.5 cm. long. S. longifolium and *S'. brevifolium J. G. Smith. Hill- 

 sides and plains: Neb. — Kans. — -N.M. — Ariz. — Nev. — -Mont. Plain — Mont. 

 Jc^S. 



5. S. Hystrix (Nutt.) J. G. Smith. Stems 1-3 dm. high, erect, scabrous 

 above; leaf-blades flat or at length involute, finely pubescent throughout, 2-12 

 cm. long, 1-2 mm. wide; spike 5-7 cm. long, erect, flexuose; empty glumes scab- 

 rous, 3-4 cm. long; lemma 7-S mm. long, minutel> pubescent, 3-awned, the middle 

 awn about 3 cm. long. Dry hills and "sage plains": Colo. — -Wyo. — Wash. — • 

 Ore. Son. — Submont. My-Jl. 



6. S. cinereum J. G. Smith. Stem 2-3 dm. high, densely grayish pubes- 

 cent; leaf-blades involute, rigid; spike 4-5 cm. long; awns 2-3 cm. long; lemma 

 7-8 mm. long, scabrous, 3-nerved towards the apex, 3-awned; lateral awns 

 2-4 mm. long, the middle one 2-3 cm. long. Dry places: Wash. — Ida. — Nev. 

 Son. My-Jl. 



7. S. ciliatum Elmer. Stem 1-2 dm. high, cinereous-pubescent just below 

 the spike; leaf-blades 5-10 cm. long, finely pilose, 3-4 mm. wide; spikes 5-7 cm. 

 long; empty glumes about 1 cm. long, gradually tapering into a divaricate awn, 

 3-4 mm. long; lemma 8 mm. long, i)ubescent or scabrous on the nerves; awn 

 3-4 cm. long. Hills: Wash. — Wyo. Submont. Je. 



8. S. insulare J. G. Smith. Stem slender, glabrous, 3-6 dm. high; leaf- 

 blades 1-1.5 dm. long, glabrous below, pubescent on the veins above, involute; 

 empty glumes 2-awned; awns divergent, scabrous, 1-2 cm. long; lenuna 8 mm. 

 long, smooth and shining, 3-cleft; middle awn divaricate, 1-2 cm. long; lateral 

 awns or teeth 1-2 mm. long. Arid places: Utah. Son. Je. 



9. S. molle J. G. Smith. Stem 3-4 dm. high, j)ubcscent; leaf-blades rigid, 

 ascending, S-15 cm. long, 3-5 mm. wide; spike 7-8 cm. long, erect, e.xserted; 

 empty glumes 4, entire or unequally bifid, subulate-setaceous, 6-7.5 cm. long, 



