GRASS FAMILY 43 



3. S. Tweedyi Scribn. Tufted perennial; stem 6-9 dm. high, smooth; 

 blades of the stem-leaves 1-1.5 dm. long, scabrous above; those of the shoots 

 usually longer; first glumes 2-2.5 cm. long, 3-nerved; the second slightly longer, 

 5-nerved, long-attenuate; awn about 7-10 cm. long, twice bent, scabrous. S. 

 comata intermedia Scribn. & Tweedy. Plains and mountains: Sask. Colo. 

 Ariz. 'Ida. Plain Submont. Je-Au. 



4. S. comata Trin. & Rup. Tufted perennial; stem 3-6 dm. high, glabrou-: 

 sheaths usually longer than the internodes, the uppermost inflated, enclosing 

 the base of the panicle; leaf -blades somewhat scabrous, involute; those of the 

 basal innovations filiform, 1-3 dm. long, those of the stem 6-15 cm. long, broader: 

 panicles 15-20 cm. long, loose; outer glumes 18-25 mm. long, glabrous; awn 1-2 

 dm. long, twice bent below. Prairies and sandy places: Alta. Xeb. X.M.- 

 Calif. Alaska. Plain Submont. Je An. 



5. S. Porteri Rydb. Tufted perennial; stems lender, 3-4 dm. high; leaf- 

 blades 4-10 cm. long, involute, filiform; branches of the panicle with 1-2 spike- 

 lets; empty glumes membranous, 5 mm. long, purplish; lemma hairy below, 

 slightly shorter; callus short, acute; awn 12-15 mm. long, plumose, with a single 

 bend. S. mongolica Porter & Coulter, not Turcz. Mountains: Colo. Tex. 

 Mont. 



6. S. Richardsonii Link. Tufted perennial; stem slender, 5-10 dm. high; 

 leaf -blades involute, filiform, 5-15 cm. long, smooth; panicle open, 7-12 cm. 

 long: branches slender, with 1-3 spikelets; empty glumes purplish, 8-9 mm. long, 

 broadly lanceolate, acute; lemma thinly pubescent; awn 12-20 mm. long, strigu- 

 lose. Hillsides and open woods: Sask. S.D. Colo. Alta. Mont. Jl-S. 



7. S. canadensis Poir. Tufted perennial; stem 3-6 dm. high, smooth or 

 somewhat scabrous; blades 5-12 cm. long, 1-2 mm. wide, scabrous; panicle 5-12 

 cm. long; outer glumes 4-5 mm. long, obtuse or acutish, glabrous, membranous; 

 lemma silky-strigose; awn 8-10 mm. long, twisted but only slightly bent. S. 

 Macounii Scribn. Sand hills and open woods: N.B. Me. Mich. Sask. 

 Boreal. Jl. 



8. S. Lettermani Vasey. Tufted perennial; stem 3-5 dm. high, slender; 

 basal leaf -blades filiform, 1-1.5 dm. long, involute, glabrous; panicle 1-1.5 dm. 

 long; branches mostly single, spikelet-bearing to near the base; empty glumes 

 6-7 mm. long, acuminate, awn-pointed, 3-nerved; awn 12-16 mm. long, once 

 bent. Hills and plains: Ida. Wyo. Colo. Submont. Jl-Au. 



9. S. pinetorum M. E. Jones. Tufted perennial; stem 2-3 dm. high, 

 slender, glabrous; basal leaves with thick brown sheaths; blades filiform, involute, 

 5-10 cm. long, glabrous; panicle narrow, 1-1.5 dm. long, barely exserted; branches 

 appressed; empty glumes purple-tinged, 7-8 mm. long, the first 3-nerved, the 

 second 1-nerved; lemma about 5 mm. long, hairy throughout but more densely 

 so at the apex; awn 12-20 mm. long, glabrous, twice bent. Open pinelands: 

 Utah. Mont. Au-S. 



10. S. Scribneri Vasey. Tufted perennial; stem erect, strict, 4-7 dm. high, 

 glabrous; sheaths close, smooth or slightly scabrous; leaf-blades 1-3 dm. long, 

 usually flat, scabrous above; inflorescence 1-2 dm. long; first glume 12-14 mm. 

 long, linear-lanceolate, acuminate, 3-nerved, the second about 10 mm. long; 

 awn 1.5-2 cm. long. Dry hills: X.M. Colo. L'tah Ariz. Son. Mont. 

 Jl-Au. 



11. S. viridula Trin. Tufted perennial; stem smooth, 3-6 dm. high; leaf- 

 blades involute, smooth or scabrous above, the lower 1-2 dm. long; stem-leaves 

 6-15 cm. long; outer glumes 7-9 mm. long, prominently 3-nerved, awn-pointed; 

 lemma 5-6 mm. long, strigose; awn 2-2.5 cm. long, twice bent, glabrous or some- 

 what scabrous. Plains and prairies: Sask. Kans. Utah Mont. Plain- 

 Submont. Jl-Au. 



12. S. columbiana Macoun. Tufted perennial; stem very slender, 3-5 dm. 

 high; basal leaf-blades 1-2 dm. long; stem-leaves much shorter; empty glumes 

 7-9 mm. long, awn-pointed; lemma silky-strigose, about 6 mm. long; awn about 

 3 cm. long, twice bent, minutely strigulose. Hills and mountains: B.C. Wyo. 

 Submont. Mont. Jl-Au. 



