ASTERACEAE. 359 



2, C. nevinii (Gray) Heeler. Herbage white-woolly; leaves 

 repandodentate; heads 30-40-flowered; otherwise as in the last. 

 Newhall, Nevin. 



Tribe 2. ASTEREAE. Aster Tribe. 



Annual or perennial herbs or rarely shrubs, with usu- 

 ally scentless herbage and alternate leaves. Receptacle 

 naked. Bracts of the involucre commonly well-imbri- 

 cated. Disk-flowers commonly yellow. Rays present or 

 wanting. Anthers not caudate. Pappus of bristles or 

 awns. Pollen grains echinate. 



Pappus of awns or scales. 



Pappus of several caducous awns; heads 



large. 3. Grindelia. 



Pappus of several short scales; heads 



small. 4. GUTIERREZIA. 



Pappus of bristles. 



Pappus of a few persistent slender bristles. 5. Pentachaeta. 

 Pappus of many persistent slender bristles. 

 Rays present. 

 Rays yellow. 



Rays without pappus. 6. Heterotheca. 



Rays with pappus like that of 

 disk-flowers. 

 Pappus of 2 kinds, the outer 



short and scale-hke. 7. Chrysopsis. 



Pappus of 1 kind only. 



Perennial glabrous or 

 pubescent herbs. 

 Heads small, in scor- 



pioid racemes, 8. Solidago. 



Heads small in cor- 

 ymbose panicles. 9. Euthamia. 

 Evergreen w^oody plants 

 with punctate, flat or 

 terete leaves. 10. Ericameria. 



Rays not yellow. 



Pappus rusty-brown; anthers 

 with slender appendages at 



apex. 15. CORETHROGYNE. 



Pappus dull white. 



Bracts in more than 2 series. 16. Aster. 

 Bracts in 1-2 series. 



Rays exceeding the disk. 17. Erigeron. 

 Rays inconspicu ous, 



shorter than the disk. 18. Leptilon. 

 Rays none. 



Outer flowers enlarged and more 



deeply cleft on the inner side. 14. Lessingia. 



