868 



CARDUACEAE 



Bracts of the inflorescence lanceolate or linear-lanceolate, acute or acuminate. 

 Leaves ciliate at the base. I. Vihga-Aureae. 



Leavas not ciliate at the base. IV. Glaberrimae. 



Bracts of the inflorescence oblong or linear-oblong, obtuse. 



Leaves, at least the basal ones, toothed; stem-leaves few; plants 1-4 dm. high. 



II. HxniTLES. 

 Leaves all entire; stem very leafy, 4-S dm. high. III. Speciosae. 



on recurved-spreading branches 



high; stem-leaves narrowly oblanceolate 



IV. GL-VBERRIMAE. 



Serotinae. 

 Radulak. 



Serotinae. 



Incan.\e. 



Wardiaxae. 



Leaves triple-veined; heads more or less secund 

 (except usually in Nos. 9 and 11). 

 Plants slender, not very leafy, 2-4 dm 



or linear. 

 Plant tall, leafy, 4-10 dm. high. 



Stem-leaves lanceolate. V. 



Stem-leaves obovate. VI. 



Leaves densely canescent. 

 Bracts not squarrose. 



Lea\es lanceolate; bracts narrowly linear-lanceolate. V. 



Leaves, at least the lower ones, oblanceolate oi" obovate. VII. 



Bracts squarrose; leaves numerous, entire, elUpdc. VIII. 



I. Virga-Aureae. 



Plants low and slender, 1-3 dm. high; inflorescence corymbiform; branches with a single 



or a few corymbose heads. 

 Heads 7-9 mm. high; inner bracts Unear-lanceolate, of about the same length as the 



flowers and pappus; plant 2-3 dm. high. 1. S. scopulonim. 



Heads 5-7 mm. high; bracts lanceolate, the inner shorter than the flowers and the 



pappas; plant usually less than 2 dm. high. 2. S. ciliosa. 



Plants stout, 3-4 dm. higli; inflorescence paniculate, but narrow; branches racemiform; 



heads 7-9 mm. high. 

 Basal leaves broadly oblanceolate, acute; stem pubescent. 3. S. rubra. 



Basal leaves narrowly oblanceolate, obtuse; stem glabrous up to the inflorescence. 



4. S. laevicaulis. 



II. HUMILES. 



Plant low, 1-1.5 dm. high; inflorescence with few heads, short, congested. 



5. S. decumbens. 

 Plant taller, 2-4 dm. high; inflorescence with many heads, elongate. 



Leaves not cUiate; bracts oblong; inflorescence usually narrow. 6. S. oreophila. 

 Leaves ciliate at the base; bracts Unear; inflorescence open. 7. S. dilatata. 



One species. 



III. Speciosae. 



IV. Glaberrimae. 



8. S. pallida. 



Heads less than 5 mm. liigh; stem slender. 



Inflorescence decidedly viscid ; leaves indistinctly triple-veined. 9. S. viscidula. 

 Inflorescence not viscid; leaves distinctly triple- veined. 



Plant glaucous; bracts thick, oblong, obtuse. 10. S. glaucophylla. 



Plant not glaucous; bracts not thick, hnear-lanceolate to oblong-lanceolate. 

 Inflorescence narrow, scarcely secund; bracts Unear-lanceolate. 



11. S. missouriensis. 

 Inflorescence usually open and more or less secimd; bracts oblong-lanceolate, j 



12. S. glaberrima. 

 Heads 6-7 mm. liigh; stem stout. 13. S. concinna. 



V. Serotinae. 



Inflorescence narrowly rhombic in outline; branches ascending, almost straight, scarcely! 



secund. 14. S. elongala. 



Inflorescence broad; branches recurved-spreading, distinctly secimd. 



Leaves green, sparingly pubescent or glabrous; pubescence scabrous, mostly confined 

 to the margins and the veins. 

 Stem usually glabrous up to the inflorescence; leaves glabrous except on the margins 

 and on tlie midveins. 

 Veins of the leaves glabrous; heads 5-6 nun. high, in a short panicle vsdth strongly 



curved brunches. 15. S. serolina. 



Veins of the leaves pubescent below; heads 4-5 mm. high; panicle with long 

 branches. 16. S. salebrosa. 



Stem more or less pubescent. 



Heads 5 mm. or more high; leaves pubescent. 17. S. polyphylla. 



Heads about 4 mm. liigh; plant comparatively slender. 



Leaves pubescent, at least on the veins. 18. S. canadensis. 



Leaves glabrous, except the scabrous-ciliolate margins. 



19. S. serra. 

 Leaves densely canescent, especially beneath. 

 Leaves usually broadly lanceolate. 



Leaves scabrous above. 20. S. dumetorum. 



Leaves softly puberulent on both sides. 21. S. pruinosa. 



Leaves linear-lanceolate, finely and rather softly canescent on both sides, more or 

 less yellowish gray. 22. S. gilvocanescens . 



