THISTLE FAMILY 869 



VI. RADULAE. 



One species. 23. S. GarretUi. 



VII. INCANAE. 



Plant low, 1-2 dm. high; inflorescence corymbiform; branches not secund. 



Bracts oval to oblong, obtuse. 24. S. nana. 



Bracts lanceolate, acute. 25. S. nivea. 



Plants tall, 2-6 dm. high; inflorescence narrow, or if open with distinctly secund branches. 

 Bracts oblong or linear, obtuse; stem-leaves scarcely triple-veined; inflorescence 



usually narrow. 



Stem-leaves oblanceolate. 26. S. pulcherrima. 



Stem-leaves spatula te or broadly oblanceolate. 27. S. radulina. 



Bracts lanceolate or ovate, acute; stem-leaves distinctly triple- veined ; inflorescence 



usually more open. 



Stem-leaves oblanceolate or elliptic; bracts lanceolate. 28. S. trinervata. 



Stem-leaves obovate, thick; bracts ovate. 29. S. mollis. 



VIII. WARDIANAE. 

 One species. 30. S. Wardii. 



1. S. scopulorum (A. Gray) A. Nels. Stem glabrous below, pilose above; 

 basal leaves 5-15 cm. long; blades oblanceolate or spatulate, usually obtuse, 

 crenate or serrate towards the apex; upper stem-leaves lanceolate or linear- 

 lanceolate, sessile; bracts acute, ciliolate; achenes strigose. S. corymbosa Nutt., 

 not Ell. S. mulliradia'a scopulorum A. Gray. Hills and mountains: Alta. 

 Colo. Utah B.C. Mont. Je-Au. 



2. S. ciliosa Greene. Stem 1-2 dm. high, decumbent at the base, glabrous 

 below, pilose above; basal leaves spatulate, serrate-crenate towards the apex, 

 2-5 cm. long, tapering into a short petiole; stem-leaves linear-lanceolate to 

 linear-oblanceolate, entire, sessile, ciliolate; heads in a small dense thyrsus; 

 achenes strigose. Higher mountains: Alta. Colo. Ariz. B.C. Mont. Alp. 

 Je-S. 



3. S. rubra Rydb. Stem about 3 dm. high, pubescent, reddish; basal and 

 lower cauline leaves 6-12 cm. long, firm, bluish green, glabrous, serrulate and 

 minutely scabrous on the margins; upper stem-leaves sessile and lanceolate; 

 bracts narrowly linear-lanceolate, ciliolate; achenes strigose. Mountains: Colo. 

 Mont. S. 



4. S. laevicaulis Rydb. Stem rather tall, 4-7 dm. high, light-colored and 

 shining; basal leaves rather thin, obtuse, 5-10 cm. long, entire or crenate, glabrous 

 except the scabrous margin; upper stem-leaves narrowly lanceolate, sessile; 

 branches nearly erect; bracts narrowly linear-lanceolate, acute, ciliolate on the 

 margins; achenes sparingly strigose. Mountains: Colo. Wyo. Jl-S. 



5. S. decumbens Greene. Stem low, decumbent at the base, glabrous or 

 nearly so; basal leaves spatulate or oblanceolate, obtuse or rounded at the apex, 

 crenate-serrate towards the end; upper leaves narrower; bracts linear or oblong; 

 heads 6-8 mm. high; achenes strigose-hirsute. A. humilis nana A. Gray. Higher 

 mountains: Wyo. N.M. Subalp. Alp. Jl-S. 



6. S. oreophila Rydb. Stem glabrous or nearly so, often tinged with red; 

 lower leaves spatulate, rounded and serrate or crenate at the apex, 3-10 cm. 

 long, glabrous; stem-leaves oblanceolate, entire or nearly so; panicle narrow; 

 heads about 8 mm. high; bracts linear; achenes hirsute-strigose. S. humilis A. 

 Gray, in part, not Nutt. Mountains: B.C. Mack. Colo. Mont. Subalp. 

 Jl-S. 



7. S. dilatata A. Nels. Stem glabrous, 4-6 dm. high; basal leaves gla- 

 brous, scabrous-ciliolate, oblong-spatulate to elliptic, 1-1.5 dm. long, serrate; 

 stem-leaves lanceolate, the upper sessile; heads numerous, in a rather open pan- 

 icle, 6-8 mm. high; bracts linear, most of them obtuse; achenes slightly hirsute. 

 Mountains: Mont. Colo. Submont. Mont. Jl-Au. 



8. S. pallida (Porter) Rydb. Stem 4-8 dm. high, glabrous; leaves obovate- 

 spatulate to lanceolate, 5-15 cm. long, acute, entire, pale; heads very numerous, 

 in a dense, elongated-conic panicle; disk 5-6 mm. high; bracts oblong or linear- 

 oblong, glabrous; achenes glabrous or nearly so. S. speciosa pallida Porter. 

 Hills: S.D. Neb. Colo. Plain Submont. Au-S. 



