934 FLORA. 



B. Tips of the involucral bracts all erect and appressed. 



♦ Heads in axillary clusters, or also in a terminal spike-like, sometimes branched 



thyrsus. 

 i. Heads 4-6 mm. high, chiefly in axillary clusters; achenes pubescent. 

 Stem and branches terete; leaves lanceolate to oblong. 4. S. caesia. 



Stem and branches grooved or angled. 



Leaves broadly oval, contracted into margined petioles. 5. S.flexicaulis. 



Leaves lanceolate, sessile. 6. S. Curtisii. 



2. Heads 4-6 mm. high, chiefly in a terminal spike-like thyrsus; achenes glabrous, or 



nearly so. 

 Rays white; stem pubescent. 7. S. bicolor. 



l< tys yellow ; stem densely pubescent. 8. S. hispida. 



ays yellow; stem glabrous, or sparingly pubescent. 



Leaves thick, not acuminate, dentate, or the upper entire. 9. S. erecta. 

 Leaves thin, acuminate, sharply serrate. 10. S. monticola. 



3. Heads 10-12 mm. high; bracts elongated, acute; leaves ovate. 



11. S. macrophylla. 



* * Heads in a terminal simple or branched thyrsus, not at all secund on its branches, 



or scarcely so. 

 1. Bracts of the involucre acute or acutish. 

 Plants not glutinous. 



High northern; leaves spatulate, glabrous. 44. S. multiradiata. 



Eastern; stem minutely puberulent or glabrous; heads 5-6 mm. high. 



12. J", puberula. 

 Western; stem and leaves scabrous or rough-pubescent. 13. S. Lindheimeriana. 



Involucre and upper leaves glutinous. 14. S. Randii. 



2. Bracts of the involucre obtuse (or the inner acutish in No. 15.) 

 a. Upper leaves abruptly smaller than the lower, appressed. 15. S. stricta. 



b. Leaves gradually smaller upward, spreading or ascending. 



f Lower leaves large, oblong, or oval, acute or obtusish. 

 X At least the lowest leaves dentate; plants 6-18 dm. high. 

 Lower leaves oblong-lanceolate; branches of the thyrsus appressed. 



16. S. uliginosa. 

 Lower leaves ovate or broadly oval; branches of the thyrsus ascending. 



17. S. speciosa. 



\ X Leaves lanceolate or oblong-lanceolate, entire, 2-12 cm. long. 18. S. rigidiuscula. 

 f f Basal leaves narrowly spatulate. 19. S. Purshii. 

 t f t Basal leaves obovate, oblanceolate, or broadly spatulate. 

 Plant 7-30 cm. high, on alpine summits; stem angular. 20. S. alpestris. 



Plant 3-9 dm. high, not alpine; heads 6-8 mm. high. 21. S. Vtrgaurea. 



* * * Heads in a terminal, usually large panicle, secund on its spreading or re- 

 curved branches. 

 % Plant maritime; leaves thick, fleshy, entire. 22. S. sempervirens. I 

 X X Plants not maritime; leaves not fleshy. 

 1. Leaves pinnately veined, not triple-nerved. 

 a. Leaves all entire, thin and glabrous. 23. -S". odora. 

 (b) Leaves, at least the lower, more or less dentate or serrate. 

 + Leaves linear or linear-oblong, 2.5-5 cm. long, scabrous. 24. S. torti/oha. 

 f t Leaves broader, lanceolate, oblong, or ovate, 5-25 cm. long. 

 X Stem densely pubescent ; leaves more or less so. 

 1 eaves rugose-vein v beneath, sharply serrate. 25. £. rugosa. 



Leaves not rugose, sparingly dentate or entire. 20. S.Jistulosa. 



X X Stem glabrous, or puberulent, or pubescent only above. 

 Leaves very scabrous on the upper surface, serrulate. 27. S. patula. 



Leaves smooth, or minutely roughened on the upper surface (pubescent in forms of 



No. 33.). 



Racemes few, widely divergent, very slender. ,./•/■ 



Lower leaves oblong, coarsely serrate. 28. b. ultmjolia. 



Lower leaves ovate or lanceolate, rather finely serrate. 29. S. Boottn. 

 Racemes numerous, spreading, recurved or ascending. . 



Leaves all oblong or oblong-lanceolate, sessile. 3°- s > t.lliotttt. 



At least the lower leaves petioled, lanceolate or ovate-lanceolate. 



Leaves firm, ovate-lanceolate or oblong-lanceolate; heads about 4 mm. high( 



racemes short ; rays several. 3«- S.negUcta. 



I . s firm narrowly lanceolate; heads about 4 mm. high: racemes lew, , 

 short; rays 1-3. * 2 - S - ^iKgulmta \ 



Leaves firm, lanceolate or oval-lanceolate; heads 3-4 mm. high; racemes 



numerous, slender. 35. S. juncea. . 



Leaves thin, the lower broadly ovate, short-acuminate: heads 5-7 mm. nign, 

 racemes numerous. 34- s - arguta. 



