COMPOSITAE 



189 



III. 



Invohiore dotted with oil glands. 36. Boebhra. 



Involucre not dotted with oil glands. 



Pappus none. 33. Flaveeia. 



Pappus of 5-8 scales. 34. Hklenium. 



Pappus of 2-3 awns. 7. Grindklia. 



Pappus a short crown. 40. Tanacetum. 



Pappus of disk flowers of capillary hristles. 

 Bracts in a single series. 44. Senecio. 



Bracts strongly imbricated. 

 Heads V or more broad. 

 Leaves spinulosely serrate. 8. Prionopsis. 



Leaves not spinulosely serrate. 17. Inula. 



Heads 6" or less broad. 

 Pappus of 5-8 bristle-like chaff. 

 Pappus of numerous capillary bristles. 

 Disk flowers more numerous than ray 



flowers. 9. 



Eay flowers more numerous than disk 

 flowers. 10. 



IV. 

 Pappus none. 39. 



Pappus of 2-4 bristles and short scales. 11. 



Pappus of numerous capillary bristles. 

 Eays not the width of the disk. 

 Bays longer than the disk. 

 Involucre imbricated in 1-2 rows. 13. Erigeron. 



Involucre imbricated in 2-several rows. 12. Aster. 



6. Amphiachyris. 



9. solidaqo. 

 euthamia. 



Chrysanthemum, 

 boitonia. 



14. Leptilon. 



Disk flowers not ripening seeds. 

 Achenes wing-margined. 

 Achenes wingless. 

 Disk flowers ripening seeds. 

 Leaves opposite. 

 Achenes 3-4 sided. 

 Eay flowers fertile. 

 Bay flowers not fertile. 

 Achenes strongly flattened. 



Pappus of two small teeth or none. 

 Pappus of 2-6 barbed bristles. 

 Leaves alternate. 

 Beceptacle conic or columnar. 

 Achenes 4-angled or terete. 

 Achenes flat, wing-margined. 

 Beceptacle flat to low conic. 

 Pappus of two small scales or awns. 

 Achenes not winged. 

 Achenes winged. 

 Pappus of 6-12 scales. 



VI. 



Involucral bracts not strongly fimbrillate. 

 Bays reddish-purple. 

 Bays white. 

 Disk flowers not ripening seeds. 



19. SiLPHIUM. 



20. Engelmannia. 



22. Heliopsis. 

 27. Helianthus. 



29. Coreopsis. 



30. BiDENS. 



24. Eudbeckia. 



25. Eatibida. 



27. Helianthus. 



28. Verbesina. 

 35. Gaillardia. 



26. Braunebia. 



