CARDUACEAE. 391 



III. OCCIDENTALES. 



Plant 2-3 dm. high ; stem-leaves obovate or oblong, clasping. 



Plant very leafy ; involucres about z cm. broad, short-peduncled or subsessile ; 



achenes strigose. 10. 5". carthamoides. 



Plant less leafy; involucres about 15 mm. broad, distinctly peduncled ; achenes 

 glabrous. 11. 5". blitoides. 



Plant about i dm. high ; stem-leaves spatulate or ovate, not clasping. 



12. 5". invenustus. 



IV. Triangulares. 



One species. 13. 6". triangularis. 



V. Serrae. 



Heads 12-15 mm. high; disk 8-15 mm. broad; whole plant dark green. 



14. 6". admirabilis. 

 Heads 8-10 mm. high; disk 5-6 mm. broad; plant light green. 



15. 6". serra. 

 VI. Crassuli. 



Stem-leaves linear or linear-lanceolate. 16. 5". lapathifolium. 

 Stem-leaves ovate or ovate-lanceolate. 



Leaves firm ; bracts thick and fleshy. 1 7. 5". crassulus. 



Leaves thin ; bracts not very thick. 18. 5". semiamplexicaulis. 



VII. Rapifolii. 

 One species. 19. 5". rapif alius. 



VIII. Hydrophili. 

 One species. 20. 5". hydrophilus. 



IX. Integerrimi. 



Bracts without black tips; leaves entire-margined. 21. 5". integerrimus. 



Bracts usually black-tipped ; leaves more or less dentate or denticulate. 

 Bracts of the involucres narrowly linear-lanceolate, long attenuate. 

 Leaves thick ; basal ones obovate, dentate. 22. S. Hookeri. 



Leaves thin ; basal ones oblanceolate or spatulate, merely denticulate. 



23. S. dispar. 

 Bracts of the involucres linear or oblong, rather abruptly acute, with lanceolate 

 or triangular tips. 

 Basal leaf-blades orbicular to broadly oval, rather abruptly contracted into 



the petioles. 24. 6". Flintii. 



Basal leaf-blades spatulate to linear-oblanceolate or rarely lanceolate, gradu- 

 ally tapering into the petioles. 

 Inflorescence even in age a flat-topped corymb ; leaves more or less dentate. 



25. S. columbianus. 

 Inflorescence with a short-peduncled terminal head and the lateral ones 



usually very long-peduncled ; leaves merely callous denticulate. 

 Basal leaves thick ; their petioles shorter than the blades. 



26. 5". perplexus. 

 Basal leaves thin ; their petioles usually longer than the blades. 



2:^. S. dispar. 



X. Glaucentes. 



One species. 27. S. anacletus. 



XI. Atrati. 



Bracts broadly linear, abruptly acute. 28. 5". alratus. 



Bracts narrowly linear, long-acute. 29. S. milliflorus. 



XII. Cani. 

 Heads 7-8 mm. high. 30. S. Purshianns. 



Heads i cm. or more high. 31. S. Harhourii. 



