STANDLEY TBEES AND SHEUBS OF MEXICO 1473 



Pedicels without stipitate glands 47. c. lanatus. 



Heads small or medium, 8 to 26-flowered (rarely to 62-flowered in forms of 

 C. veronicaefolius) . 

 Leaves sessile or very short-petioled. 



Leaves spatulate, 3 to 12 mm. long 4. c. frutescens. 



Leaves not spatulate, usually larger. 



Leaves 1 to 2 cm. long, suborbicular-ovate; outer phyllaries more or 



less squarrose-tipped 5. C. microphyllus. 



Leaves larger, not suborbicular. 



Leaves lanceolate to oblong or elliptic, not cuspidate, not cordate 

 at base. 

 Heads about 10-flowered. 



Phyllaries numerous (about 40) ; achenes aboVit 5 mm. long. 



6. C. cylindraceus. 

 Phyllaries few (about 15); achenes about 3 mm. long. 



7. C. lemmoni. 

 Heads 14 to 24-flowered. 



Heads (at least in part) slender-pediceled. 

 Leaves crenate or crenate-serrate. 



Outer phyllaries suborbicular, rounded or retuse and 



abruptly mucronate 8. C. venosus. 



Outer phyllaries ovate or ovate-oblong, usually acute or 



acuminate 9. C. oliganthes. 



Leaves entire 10. C. reticulatus. 



Heads sessile or subsessile. 



Phyllaries thin, colored, with very acuminate tips. 



11. C. verbenaceus. 

 Phyllaries thick, usually stramineous, with obtuse tips. 



12. C. pringlei. 

 Leaves ovate or oval-ovate, cordate at base, strongly cuspidate. 



13. C. cuspidatus. 

 Leaves distinctly petioled, the petiole at least one-fifth as long as the 

 blade. 

 Leaves more or less hastately toothed or lobed. 



Leaves lance-oblong or lanceolate, rounded at apex. ._ 14. C. hastatus. 

 Leaves deltoid-ovate, acuminate, or rarely obtuse but then not lance- 

 oblong. 

 Outer phyllaries ovate-lanceolate, acute or acuminate. 



Leaves 1.5 to 2.5 (rarely 6.5) cm. long, thickish; petioles 8 to 15 mm. 



long 15. C. coulteri. 



Leaves 4.5 to 7 cm. long, thin; petioles 1.2 to 4 cm. long. 



16. C. megalodontus. 

 Outer phyllaries ovate-oblong or suborbicular, obtuse or rounded. 

 Phyllaries scarious-margined, mucronulate. 



Grayish-pubescent; leaves membranaceous, acutely acuminate. 



17. C. brachiatus. 



Glabrous; leaves thick, often obtuse 18. C. glabratus. 



Phyllaries scarcely scarious-margined, not mucronulate. 



19. C. cymuliferus. 

 Leaves not at all hastate. 



Leaves broadly ovate to suborbicular or reniform, mostly 0.5 to 2 

 (rarely 6) cm. long; heads smaller, often glomerate. 

 Involucre 5 to 9 mm. high. 



Outer pliyllaries shortly caudate; leaves very small, flabellate- 

 rhomboid 20. C. glutinosus. 



