BLAKE. — ENCELIA AND RELATED GENERA. 377 



Key to the Species of Simsia. 



A. Rays purple 22. S. sanguinea. 



A. Rays yellow or wanting. 

 B. Leaves silky beneath. 



C. Achenes glabrous 19. S. Ghiesbreghtii. 



C. Achenes appressed-pubescent 20. S. sericea. 



B. Leaves densely canescent-tomentose beneath S. S. Sodiroi. 



9. S. pubescens. 

 B. Leaves neither silky nor densely canescent-tomentose beneath. 

 C. Petiole-bases connate, forming foliaceous disks. 



D. Involucral scales subequal 1. S. calva. 



D. Scales 3-4-seriate. 



E. Leaves hastately lobed; stems glandular-setose. 2. S.setosa. 

 E. Leaves unlobed; stems merely glandular. . . .3. »S'. tenuis. 

 C. Petiole-bases not connate into foliaceous disks. 

 D. Involucral scales 3-4-seriate, the outer ovate. 

 E. Achenes glabrous and awnless. 



F. Petioles not auriculate 4. S. exaristata. 



5. S. submollicoma. 



F. Petioles auriculate 6. *S. eurylepis. 



E. Achenes pubescent, 2-awned. 



F. Pales and scales purple-tipped; achene 5 mm. long. 



7. S. Ingascaeformis. 

 F. Pales scarcely purple-tipped; achenes 6-7 mm. long. 



10. S. Chaseae. 

 D. Scales subequal, or the outer if shorter lance-oblong to linear- 

 lanceolate. 

 E. Leaves 3-lobed, the lobes narrow, sessile by a margined base; 



achene 5-6 mm. long 21. S. triloba. 



E. Leaves unlobed, or the lobes if present broad, and the 

 achene 4-4.5 mm. long. 

 F. Achenes 6-7.3 mm. long. 



G. Leaf blade broadly deltoid, abruptly narrowed to a 

 broadly margined clasping base; Mexican. 



18. S. megacephala. 



G. Leaves not clasping, grayish beneath with tubercu- 



late-based hairs; South American. .14. S. hirsuta. 



15. S. Dombeyana. 

 G. Leaves not clasping, densely glandular-dotted both 



sides; Jamaican 13. S. jamaicensis. 



F. Achenes 4-5.3 (-6) mm. long. 



G. Whole plant densely covered with stalked glands. 



12. S. adenophora. 

 G. Glands less prominent. 



H. Involucral scales herbaceous, scarcely striate; 



leaves mostly lobed, generally auriculate-clasiJ- 



ing; Mexican & Guatemalan. . . .11. S.foetida. 



H. Scales corky-ribbed at base; heads large, disk 



2-3 cm. in diameter; Central American. 



16. *S. grnndiflora. 

 H. Scales not corky-ribbed; heads smaller, disk 



1.2-1.7 cm. in diameter; Central American. 



17. S. polycephala. 



