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. S. carthamoides. 



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



glabrous. n. S. blitoides. 



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



12. S. invenustus. 



IV. TRIA.NGULARES. 



One species. 13. 6". triangnlaris. 



Y. SERRAE. 



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



14. .S 1 . adniirabilis. 

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



15. 5". serra. 

 VI. CRASSULI. 



Stem-leaves linear or linear-lanceolate. 

 Stem-leaves ovate or ovate-lanceolate. 



Leaves firm ; bracts thick and fleshy. 



Leaves thin ; bracts not very thick. 



One species. 

 One species. 



VII. RAPIFOLII. 



VIII. HYDROPHILI. 



IX. INTEGERRIMI. 



16. 5". lapathifolium. 



1 7. 6". crassulus. 



1 8. .S. sctmamplexicaulis. 



19. S. rapifoliits. 



20. 5". hydrophilus. 



Bracts without black tips; leaves entire-margined. 21. 6". 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. 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. 



25. 5. coiumbianns. 

 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. perplcxus. 

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



23. 5". dispar. 



X. GLAUCENTES. 



One species. 



XI. ATRATI. 



Bracts broadly linear, abruptly acute. 

 Bracts narrowly linear, long-acute. 



XII. CAN r. 



Heads 7-8 mm. high. 

 Heads i cm. or more high. 



27. 5". anacletus. 



28. S. atratus. 



29. S. niilli floras. 



30. -5". Piirshiaims. 



31. 6". Harboitrii. 



