STANDLEY TREES AND SHRUBS OF MEXICO 1435 



Petiole one-fourth to one-third as long as blade. 



Leaves elliptic-lanceolate to ovate-oblong, pointed at 



base, smoothish 79. E. glabratum. 



Leaves deltoid-ovate, subtruncate to cordate at base, 



pubescent, crenate-dentate 35. E. azureum. 



Outer and middle phyllaries acute, the inner obtuse. 



Leaves over 10 cm. wide, unlobed 36. E. oresbium. 



Leaves with 1 or 2 sharp lobes or angles on each side. 



37. E. oresbioides. 

 Leaves 2 to 6 cm. wide, unlobed. 

 Heads 12 to 30-flowered. 



Involucre less than half as long as florets, glutinous. 



79. E. glabratum. 

 Involucre at least two-thirds as long as florets. 



Leaves cuspidate-denticulate, pinnateh' nerved from 

 well above the base; phyllaries scarcely nerved 



or striate 38. E. hylobium. 



Leaves serrate to crenate, 3 or 5-nerved from the 

 base; phyllaries distinctly nerved or striate. 

 Heads about 1 cm. long; leaves cordate with a 

 narrow sinus, prominently reticulate-veiny be- 

 neath 50. E. phoenicolepis. 



Heads 4 to 6 mm. long; leaves acute to rounded or 

 openly cordate at base, not reticulate-veiny. 



39. E, pycnocephalum. 

 Heads 6 to 8-flowered; phyllaries pearly white. 



45. E. leucocephalum. 

 Phyllaries all obtuse or rounded at tip. 

 Leaves sessile. 



Cauline leaves alternate 40. E. adenospermum. 



Cauline leaves opposite 41. E. dryophilum. 



Leaves petioled. 



Heads 1-flowered, in panicled glomerules. 



42. E. monanthum. 

 Heads several to many-flowered. 



Heads in subglobose axillary glomerules. 



43. E. pelotrophum. 

 Heads not in axillary glomerules. 



Heads about 6-flowered. 



Heads about 1 cm. long 44. E. canipechense. 



Heads about 5 mm. long.45. E. leucocephalum. 

 Heads 10 to 12-flowered. 



Leaves hastate; pedicels commonly 6 to 10 mm. 

 long. 

 Florets about twice as long as inner phyllaries; 

 leaves somewhat fleshy. 



46. E. peninsulare. 

 Florets scarcely exceeding inner phyllaries; 

 leaves membranaceous. 



47. E. spinaciaefolium. 



Leaves ovate, not hastate; pedicels to 3 mm. long. 



20. E. hemipteropodum. 



