44 POACEAE 



13. S. arida M. E. Jones. Densely tufted perennial; stem erect, about 3 

 dm. high, smooth; blades 3-10 cm. long, filiform, involute, smooth; panicle nar- 

 row, 1-1.5 dm. long; lower branches in 5's, short; empty glumes lanceolate, 

 acuminate, 8-10 mm. long; lemma 4 mm. long, glabrous above, short-pubescent 

 below; awn 3-5 cm. long, slender, glabrous, only slightly bent. Dry hillsides: 

 Utah Colo. Son. Submont. My-Je. 



14. S. Nelsonii Scribn. Tufted perennial; stem stout, 7-9 dm. high, smooth; 

 leaf-blades 1-3 dm. long, those of the innovations narrow and involute; stem- 

 leaves 2-4 mm. wide and often flat; panicle 1.5-3 cm. long; first glume 9-10 mm. 

 long, 3-nerved; second glume slightly longer, 5-nerved; lemma 7 mm. long, 

 almost cylindric, silky-strigose; awn about 3.5 cm. long, minutely scabrous. 

 Plains, hills, and canons: Sask. Colo. Utah Ida. Alta. Submont. Mont. 

 Jl-Au. 



15. S. minor (Vasey) Scribn. Densely tufted perennial; stem smooth, 3-6 

 dm. high; leaf -blades 1-3 dm. long, 2-3 mm. wide, usually strongly involute, 

 scabrous on the margin; panicle purplish, 5-12 cm. long; empty glumes faintly 

 3-nerved near the base; lemma thinly strigose; awn minutely scabrous, about 

 2 cm. long. Mountain sides: Mont. N.M. Utah. Submont. Subalp. 



16. S. Vaseyi Scribn. Densely tufted perennial; stem 1-2 m. high, stout, 

 often 1 cm. thick below; sheaths usually broad and loose, hairy at the junction 

 of the blades; blades of stem-leaves usually flat, 3-6 dm. long, scabrous, those of 

 the innovations narrower, involute; panicle 2.5-4 dm. long, dense; empty glumes 

 nearly equal, lanceolate, about 1 cm. long, acuminate; lemma about 8 mm. long, 

 silky-strigose; awn 2.5-3 cm. long, minutely scabrous. Hills and mountain 

 sides: Tex. Colo. Ida.; Mex. Son. Mont. My-Au. 



17. S. Williamsii Scribn. Tufted perennial; stem 7-9 dm. high; leaf- 

 blades 1.5-3 dm. long, pubescent on the back, scabrous above; empty glumes 

 lanceolate, long-acuminate, 6-8 mm. long; lemma about 6 mm. long, finely 

 strigose; awn about 2.5 cm. long, minutely scabrous. Dry soil: Wyo. Mont. 

 Submont. Mont. Jl-Au. 



18. S. Elmeri Piper & Brodie. Tufted perennial; stem 3-6 dm. high, 

 glabrous or somewhat pubescent; lower leaf -blades slender and involute, those of 

 the stem broader, often flat, 5-15 cm. long; inflorescence 1-2 dm. long; empty 

 glumes 10^12 mm. long, acuminate, hyaline, 3-nerved; lemma about 7 mm. long, 

 finely strigose; awn 3-3.5 cm. long, sub-plumose up to the second bend. 

 Meadows and fields: Wash. Wyo. s Calif. Submont. Je-Au. 



19. S. oregonensis Scribn. Tufted perennial; stem 3-5 dm. high, glabrous; 

 uppermost sheath loose, enclosing the base of the panicle; basal leaf -blades in- 

 volute-filiform, 1-2 dm. long; upper stem-leaves 4-6 cm. long; panicle 8-16 cm. 

 long, narrow; outer glumes narrowly lanceolate, acuminate, 3-nerved, 10 mm. 

 long; lemma 7-8 mm. long, thinly pubescent; awn 2.5-3.5 cm. long, sub-plumose 

 on the lower half. S. stricta Vasey, not Lam. S. occidentalis Piper, not Thurb. 

 Ridges and bench-lands: Wash. Wyo. Calif. Submont. Jl-S. 



20. S. Thurberiana Piper. Tufted perennial; stem 3-10 dm. high, some- 

 times tinged with purple, scabrous or puberulent, often pubescent at the nodes; 

 sheaths close, usually puberulent; blades 1-2 dm. long, or the upper shorter, 

 involute; panicle 7-15 cm. long, with the base often included; first glume 1 cm. 

 long, 5-nerved, the second shorter, 3-nerved; lemma 6-7 mm. long, strigose; awn 

 3-4 cm. long, plumose below the bend. Dry plains: Wash. Ida. Nev. Calif. 

 Submont. Son. Je-Jl. 



21. S. speciosa Trin. & Rup. Tufted perennial; stem 3-6 dm. high; lower 

 sheaths more or less pubescent, the upper glabrous and loose; lower leaf-blades 

 1-3 dm. long, usually involute; panicle 1.5-2 dm. long, included below; empty 

 glumes hyaline, long-acuminate; lemma 10-12 mm. long, pubescent; awn 4-5 

 cm. long, long-plumose below, glabrous above, with a single bend. Hills: 

 Calif. Utah Ariz.; Mex. Son. My-Jl. 



