850 CARDUACEAE 



Leaves oblong or lanceolate, decidedly acute, those subtending tlie 



heads narrowly linear. 4. C. fuiiosa. 



Leaves oblanceolate or obovate. those of the inflorescence elliptic or 

 oval. 

 Disk of the heads about 1 5 mm. broad ; leaves strigose. 



Inner bracts with subulate, usually brownish and spreading tips. 



5. C. caudal a. 

 Inner bracts merely acute. 6. C. aniplifolia. 



Disk of the heads 10-12 mm. broad; leaves hirsutulous. 



7. C. imbricata. 

 Heads pedimcled, naked or rarely subtended by one small leaf. 



Plant less than 1 dm. high; heads solitarj- at the ends of the branches. 



8. C. depressa. 

 Plant 2-3 dm. high; heads more or less corymbose. 



Heads long-peduncled ; peduncles 2-7 cm. long. 9. C. pedunculala. 



Heads short-peduncled. 



Plant finely silvery-canescent, scarcely at all hirsute. 



10. C. mollis. 

 Plant usually grayish-green, conspicuouslj- hirsute on the stem; leaves 

 hirsute-ciUate towards the base. 

 Most of the leaves sessile. 



Leaves oblanceolate or obovate, obtuse or merely apiculate; disk 



of the heads 15-20 mm. broad. 11. C. villosa. 



Leaves narrowly oblanceolate, decidedly acute; disk '10-12 mm. 

 broad. 12. C. hirsutissima. 



Most of the leaves distinctly petioled; disk 10-12 mm. broad. 



Involucre more than 1 cm. liigh and broad ; leaves oblanceolate. 



13. C. Bakcri. 

 Involucre scarcely 1 cm. high and broad; leaves Unear-oblance- 

 olate. 14. C. floribunda. 



Involucre liirsute or both liirsiite and resinous-granuUferous. 



Leaves lanceolate, acute or acuminate, sessile; plant densely hirsute witli long 



white hairs. 15. C. barbata. 



Leaves oblanceolate, oblong, obovate or oval; plant not conspicuously long-hairy. 

 Involucre densely liiisute, scarcely at aU resinous-granuUferous. 



Leaves short, 1-2 cm. long, oboVate, nearly all sessile. 16. C. Butlcri. 

 Leaves oblanceolate, the lower petioled. 



Plant 1-2 dm. high; heads usually sohtary and sessile. 



17. C. ptanila. 

 Plant 2-3 dm. high; heads peduncled and corymbose. 



Disk of the heads 8-10 mm. broad; leaves densely hirsute, not 

 resinous, only the lower petioled. 18. C. Columbiana. 



Disk of the heads 12-18 mni. wide; leaves distinctly resinous-granu- 

 liferous, nearly all petioled. 19. C. grandis. 



Involucre sparmgly hirsute, copiously resinous-granuUferous. 



Upper leaves obovate, oval, only rarely oblong or broadly oblanceolate, J 

 sessile. 

 Heads sessile, subtended by oblong or obovate leaves. 



Leaves niunerous, ascending, 3-5 cm. long; involucre about 1 craj 



liigh. 20. C. resinolcns. I 



Leaves scattered, spreading, 1-2 cm. long; involucres 8-9 mm. liighl 



21. C. fulcrata. 

 Heads peduncled, naked or subtended by small linear leaves. 



Ijcaves densely hispid, not conspicuously granuliferous. 



22. C. horrida. 

 Leaves conspicuously granuUferoiis, only sparingly hispidulous. 



23. C. viscida. 

 Upper leaves as well as the lower oblanceolate, most of them petioled. 



Leaves broadly oblanceolate; heads pedmicled. 

 Leaves decidedly hairy, sparingly granuliferous. 



Stem smiple to near the top. 24. C. asprcUa. 



Stem profusely branched. 14. C. floribunda. 



Leaves sparingly hairy, conspicuously granuliferous. 



25. C. hispida. 

 Leaves narrowly Unear-oblanceolate; heads subsessile. 



26. C. stenophylla. 

 Heads discoid; leaves lanceolate, hispid-ciliate, otherwise glabroxis, minutely granu- 



Uferous. 27. C. orcgana. 



1. C. angustifolia Rydb. Stems erect, 2-4 dm. high, canescent and more 

 or less hirsute; leaves 2-5 cm. long, 2-5 mm. wide, acute, grayish-strigose, his- 

 pid-ciliate; involucres tuibinate-campanulate, 8-10 mm. high; bi-acts narrow and 

 linear, acute; ligules about 1 cm. long. C. stenophylla Britt. & Brown, not Greene. 

 Sandy places: AK;^.. — Kans. Plain. Au-S. 



2. C. caespitosa M. E. Jones. Cespitose from a woody root, forming a ^ 

 mat; stems spreading, 5-8 cm. long, villous-hirsute ; leaves spatulate, villous-] 

 canescent, apiculate; heads sessile; involucres 6 mm. high; bracts ashy-strigose, 



