STANDLEY TREES AND SHRUBS OF MEXICO. 1217 



Leaves mostly 5 cm. long or much larger. 



Leaves densely pilose, tomentose, or sericeous beneath, even in age. 



Leaves densely whitish-sericeous beneath 6. C. elaeagnoides. 



Leaves tomentose or pilose beneath with loose spreading hairs. 



Flowers 2 cm. long 7. C. guerkeana. 



Flowers 2.5 to 4.5 cm. long. 



Leaves densely tomentose beneath 8. C. boissieri. 



Leaves hispidulous beneath with short, very stiff hairs. 



9. C. morelosana. 

 Leaves glabrous beneath in age except along the costa, or with small 

 inconspicuous hairs along the veins. 

 Calyx lobes subulate or narrowly deltoid, acute. 



10. C. gerascanthus. 

 Calyx lobes broadly ovate or deltoid, obtuse. 



Calyx 6 to 7 mm. long, minutely puberulent 11. C. igualensis. 



Calyx 9 to 14 mm. long, densely pubescent. 



I Slender portion of the corolla tube much exserted from the 



calyx 12. C. tinifolia. 



Slender portion of the corolla tube not or scarcely exserted. 



13. C. sonorae. 

 Calyx neither striate nor sulcate. 

 Flowers in cymes. 



Corolla 12 to 16-lobate 14. C. dodecandra. 



Corolla 5 to 8-lobate. 



Flowers 6 mm. long or less 15. C. chiapensis. 



Flowers more than 1 cm. long. 

 Calyx 5 to 6 mm. long; leaves tomentose beneath, at least when 



young ^ 16. C. microsebestena. 



Calyx 8 to 14 mm. long; leaves not tomentose beneath. 

 Leaves setulose-hirtellous beneath ; flowers mostly 3.5 to 4.5 cm. 



long 17. C. sebestena. 



Leaves minutely scaberulous or glabrate beneath ; flowers less than 



3 cm. long 4. C. seleriana. 



Flowers in spikes or globose heads. 

 Flowers in dense globose heads. 

 Leaves stellate-pubescent on the upper surface. 



Calyx lobes filiform 18. C. pringlei.* 



Calyx lobes short, obtuse : 19. C. stellata. 



Leaves without stellate pubescence. 



Flower heads paniculate 20. C. corTmbosa. 



Flower heads solitary. 

 Calyx lobes subulate or filiform. 

 Stems and peduncles hispid with spreading hairs. 



21. C. urticacea. 

 Stems and peduncles puberulent or tomentulose, often also ap- 

 pressed-setulose. 

 Corolla 1.5 cm. long or less. 



Leaves sparsely strigose or strigillose 22. C. limicola. 



Leaves setose-scabrous 23. C. globosa. ■ 



Corolla 2 cm. long or more. 



Leaves acute or attenuate at base 24. C. perlonga. 



Leaves mostly obtuse or rounded at base. 



25. C. appendiculata. 



