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. molle. 



Lemma scabrous. 10. S. strigosum. 



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. 



4wns of the lemma 4-7 cm. long; plant taller, more than 2 din. high. 

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



Plant perfectly glabrous; awn ascendhig. 12. S. glahrum. 



Plant puberulent or scabrous; awns divergent. 



13. S. montanum. 



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



14. 5. basallicola. 



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

 blacles 8-15 cm. long, 2-3 mm. wide, rigid; spikes erect, 6-10 cm. long, barely 

 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 silanioides J. G. Smith. Mountains: Mont. — S.D. Suhmonl. Au. 



2. S. marginatum Scribn. & Merrill. Stem 2-3 dm. hip^h; 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. pubiflonim 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. brevifoUum J. G. Smith. Hill- 

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

 Je-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 l 

 rous, 3-4 cm. long; lemma 7-8 mm. long, minutel^^ pubescent, 3-awned, the middle 

 SLwn about 3 cm. long. Dry hills and *'sage plains": Colo. — Wyo. — Wash. 

 Ore. Son, — Submont. My-Jh 



6. S. clnereum 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. 

 iSon. Mv-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, pubescent or scabrous on the nerves; awn 

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



8. S. insular© 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; lemma 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, pubescent; leaf-blades rigid, 

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

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



