854 CARDUACEAE 



Leaves and branches wliitotomentose. 



Leaves mostly erect, the upper reduced, not exceedmg the heads. 



6. C. Newberryi, 



Leaves arcuate-spreading, the upper longer than the heads. 



7. C. Howardli. 



Outer bracts short, neither produced nor foHaceous, 

 Heads 5-8 mm. high; bracts thin, glabrous. 



Leaves 2-3 cm. long, over 1 mm. wide, light green. 



8. C. Greenei, 



Leaves 1-2 cm. long, less than 1 mm. wide, dark green. 



9. Cfilifolius. 



Heads about 1 cm. long; bracts thicker. 



Leaves l&ss than 1 nxm. wide; bracts glabrous. 10. C albidu.'i. 

 Leaves 1 ram. broad or broader; bracts arachnoid-ciliate. 



Leaves 1-2 cm. long; involucre lanate as well as arachnoid. 



11. C collinus. 



Leaves 3-6 cm. long; involucre somewhat viscid, merely arachnoid- 

 ciliate on the margin. 12. C. wyomingensis. 

 Bracts not acuminate. 



Bracts 6-7 in each vertical row. 13. C. formosus. 



Bracts 3-5 in each vertical row. 



Achenes pubescent; bracts acute or obtuse. 



Branches, at least when young more or less whitened with a pannose tomen- 

 ^ turn; style-appendages longer than the stigmatic portion; corolla 7-12 



. mm. long. 



Bracts and mature leaves perfectly glabrous. 



Bracts ovate, or the outer triangular; involucre about half as long as 



the flowers. 14. C. virens. 



Bracts lanceolate to linear; involucre more than half as long as the 



flowers. 

 Leaves nearly erect or strongly ascending, straight, 1-2 mm. wide. 



15. C. graveolcns. 



Leaves scarcely 1 nun. wide. 



Leaves spreading or reflexed, more or less falcate; lobes of the 



corollas lanceolate, mostly acute. 16. C. patens. 



Leaves erect, about 0.5 mm. wide; lobes of the corolla ovate, 



obtuse, about 0.5 mm, long, erect in age. 



17. C, pinifohus. 



Bracts erose-ciliate on the margin, or tomentose, or both. 



Inflorescence elongate-thyrsoid. 18. C. concolor. 



Inflorescence corymbiform, flat or roimd-topped. 



Bracts lanceolate, acute; leaves le^s than 2.5 mm. wide. 



Bracts more or less erose-ciliate on the thin margins. 



Mature leaves glabrous or nearly so, about 1 mm. wide, erect. 



19. C. oreophilus. 



Matiu'e leaves more or less densely white-tomentose; bracts 



lanceolate. 



Leaves 1 nun. wide or less, spreading. 



20. C. pJattensis. 



Leaves 1-2.5 mm. wide. 



Bracts narrow, linear-lanceolate, strongly carinate, 

 almost glabrous, except the erose-ciliate margins. 



21. C. pulcherrimus. 

 Bracts usuallj^ broader, more or less densely tomentose 



and viscid as well as ciliate. 

 Stems eaually leafy throughout; leaves all alike, 

 strongly ascending; bracts strongly carinate. 



22. C. frigidus. 



Stems more leafy towards the ends; upper leaves 

 much shorter; bracts slightly carinate. 



23. C. pallidus. 

 Bracts not at all ciliate on the tliicker margin, but white-tomen- 

 tose on the back. 



Bracts scarcely carinate; older branches not densely and 



thickly woolly. 24. C speciosus. 



Bracts strongly carinate; older branches densely and thickly 

 woolly. 25. C nauseosus. 



Bracts elliptical, nearly glabrous, the thinner ones obtuse; leaves 

 3-4 mm. wide. 26. C. salicifolius. 



Branches without tomentum; style-appendages shorter than the stigmatic por- 

 tion; corolla 5-7 mm. long. 



Leaves and the white or straw-colored stem glabroiis or nearly so, except 



the hispidulous-ciliate margins of the former. 

 Leaves narrowly linear, 2 mm. wide or less. 



Bracts neither strongly carinate nor with conspicuous green tips. 

 Leaves less than 1 mm. wide, 1-nerved. 



Bracts linear, the innermost rounded at the apex. 



^ , , 27. C. stenophyllus. 



Bracts ovate-lanceolate, acute. 28. C. laricinus. 



Leaves 1-2 mm. wide, 3-nerved; bracts lanceolate. 



29. C. pumilus. 



