CARDUACEAE. 391 



III. OCCIDENTALES. 



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



Plant very leafy ; involucres about 2 cm. broad, short-peduncled or subsessile ; 



achenes strigose. 10. 5. carthamoides. 



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

 glabrous. 11. S. blitoides. 



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



12. 6'. inveniistus. 



IV. Triangulares. 



One species. 13. .S. triangularis. 



V. Serrae. 



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



14. 6". admirahilis. 

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



15. 5'. serra. 

 VI. Crassuli. 



Stem-leaves linear or linear-lanceolate. 16. S. lapathifolium. 

 Stem-leaves ovate or ovate-lanceolate. 



Leaves- firm; bracts thick and fleshy. 17. 5'. crassuhis. 



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



VII. Rapifolii. 

 One species. 19. 5'. rapif alius. 



VIII. Hydrophili. 

 On^ species. 20. .S". 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. 6'. 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. 5'. 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. 



23. 5'. coiumbianus. 

 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. S. perplexus. 

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



2:^. S. dispar. 



X. Glaucentes. 



One species. 27. 5'. anacletus. 



XL Atkati. 



Bracts broadly linear, abruptly acute. 28. S. atratus. 



Bracts narrowly linear, long-acute. 29. 5'. milliAorus. 



XII. Cani. 

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



Heads i cm. or more high. 31. 5'. Harbourii. 



