870 CARDUACEAE 



9. S. viscidula Rydb. Stem low, about 2 dm, high, finely pubescent, 

 reddish; lower leaves narrowly linear-oblanceolate, finely puberulent and some- 

 what viscid, denticulate, obtuse or acutish; inflorescence paniculate but flat- 

 topped; branches scarcely secund; heads nimierous, small, about 5 mm. high; 

 bracts linear, obtusish, viscid; achenes strigose. Mountains: Colo. Mont, Au. 



10. S. glaucophylla Rydb. Stem slender, pale, glabrous; leaves glabrous, 

 minutely ciliolate on the margins, rather thick, linear-oblanceolate or the upper 

 linear, 6-10 cm. long, entire, acute; inflorescence a round-topped panicle; heads 

 about 5 mm. high; achenes slightly strigose-hirsute. Valleys: Mont. — Wyo. 

 Plain — SuhmonL Jl-S. 



11. S* missouriensis Nutt. Stem slender, 3-4 dm. high, glabrous; leaves 

 linear-oblanceolate, glabrous, scabrous-ciliolate, 5-15 cm. long, acute, the lower 



getioled and sometimes serrate, the upper sessile and entire; heads 4-5 mm. high; 

 racts acute, glabrous. S, Tolmieana A. Gray. Mountains: B.C. — Ore. — Colo. 

 — S.D. — Alta. Submonl, Jl-Au. 



12. S. glaberrima Martens. Stem 2-4 dm. high, glabrous up to the in- 

 florescence; lower leaves narrowly oblanceolate, 3-15 cm, long, often serrate or 

 entire, glabrous, ciliolate; inflorescence flat-topped or round-topped; heads about 

 5 mm. high; achenes sparingly hirsutulous. S. missouriensis A. Gray, not Nutt. 

 Plains and hills: Mich. — Mo. — Tex.— Ariz. — Ida. — Alta. Plain — MonL Jl-S. 



13. S. concinna A, Nels. Stem glabrous, 2-4 dm. high, densely leafy; 

 basal leaves oblanceolate, 8-15 cm. long, serrate or entire; stem-leaves narrowly 

 oblanceolate or linear-oblong; panicle round-topped, usually open; bracts oblong, 

 acute, thin-margined; achenes pubescent. *Si. missouriensis extraria A. Gray. 

 Mountains: Alta. — Colo.— B.C. SuhmonL — Mont. Jl-S. 



14. S. elongata Nutt. Stem 3-10 dm. high, glabrous below, finely puberu- 

 lent above; leaves narrowly lanceolate, acimiinate, 5-10 cm. long, distantly 

 serrate, with sharp teeth, more or less puberulent; heads about 5 mm. high; 

 bracts linear or linear-lanceolate, acute; achenes sparingly hirsutulous. Low 

 groimd: B.C. — Mont. — Nev.— Wyo.— Calif. SuhmonL Jl-S. 



15. S. serotina Ait. Stem 5-20 dm. high; leaves lanceolate, 5-15 cm. long, 

 sessile, usually sharply serrate; inflorescence short-pyramidal, dense; bracts 

 linear or linear-lanceolate, obtuse or acutish; achenes hirsutulous. S, Pitcheri 

 Nutt., the western form, with shorter inflorescence. Meadows, valleys, and 

 along streams: Newf.— Ga. — Ark. — Colo.— B.C. Plain— SuhmonL Jl-S. 



16. S. salebrosa (Piper) Rydb. Stem 5-20 dm, high; leaves narrowly 



lanceolate, sessile, sharply serrate, acuminate or the uppermost entire, 5-10 cm. 



long, thick; panicle large; bracts narrowly linear, acutish; achenes hirsutulous. 



S, serotina salebrosa Piper. Along streams: B.C. — Mont,--Ore. SuhmonL Jl- 

 Au. 



17. S. polyphylla Rydb. Stem tall, sometimes a meter high, strict, simple 

 and puberulent up to the more hirsutulous inflorescence; leaves narrowly lanceo- 

 late, sessile, acuminate, serrate above the middle, thick and firm, green, sca- 

 brous above, more softly short-pubescent beneath; bracts linear, acute; achenes 

 hispidulous. Perhaps not distinct from the eastern S, altissima L. Along 

 streams: Wyo. — N.AI. SuhmonL Au-S. 



18. S. canadensis L. Stem 6-15 dm. high; leaves sessile. 5-10 dm. long, 

 rarely 1.5 cm. wide, narrowly lanceolate, acimiinate. serrate, puberulent on both 

 sides or glabrous above; panicle large, broadly conic; bracts narrowly linear or 

 lance-linear, acute or obtusish; achenes sparingly hairy. Among bushes: Lab. — 

 W.Va.— Colo.— B.C. Plain— SuhmonL Jl-0. 



19. S. serra Rydb. Stem about 6 dm. high, more or less pubescent, especially 

 above; leaves lanceolate, about 8 cm. long, acuminate, sharply toothed, rather 

 thm; heads numerous 3-4 mm. high; bracts linear or linear-lanceolate, acute; 

 achenes hirsutulous. Along streams: Colo. — Wyo. MonL Au. 



20. S. dumetorum LunelL Stem 5-10 dm. high, densely puberulent; 

 leaves lanceolate, acute, thick, more or less serrate, strongly veined, revolute 



