34 • The Ohio Journal of Science [Vol. XVIII, No. 2, 



2. Pappus of numerous capillary bristles. 



a. Pappus a single series of capillary bristles. 



(1) Bracts of the involucre two to many series. 



(a) Involucre narrow, its bracts firm; rays few, white. 



Sericocarpus. 



(b) Involucre turbinate or hemi-spherical, its bracts mostly thin; 



rays usually more numerous, white to purple. Aster. 



(2) Bracts of the involucre mostly in one or two series; heads mostly 



long pedicled. 



(a) Rays longer than the disk flowers. Erigeron. 



(b) Rays not longer than the disk flowers; heads very small, 



panicled. Leptilon. 



b. Pappus distinctly double, the outer series shorter than the inner. 



(1) Leaves lanceolate-ovate to obovate; rays white. Doellingeria. 



(2) Leaves narrowly linear; rays violet. louactis. 



Key to the Genera. 



1. Ray flowers yellow. 2. 



1. Ray flowers not yellow. 5. 



2. Leaves punctate, linear or linear-lanceolate; heads small, corymbose, some- 



what glutinous. Eiithamia. 



2. Leaves not punctate in our species. 3. 



3. Pappus in 2 series, the inner of long, the outer of short somewhat chaffy 



bristles; stem leaves entire. Chrysopsis. 



3. Pappus of nearly equal bristles; leaves mostly serrate or dentate. 4. 



4. Pappus of 2-8 coarse deciduous bristles; heads large, sometimes glutinous. 



Grindeha. 



4. Pappus of numerous capillary bristles; heads comparatively small, not 



glutinous. Solidago. 



5. With single flowers on leafless scapes; pappus of the disk flowers none. Bellis. 



5. Flowers on leafy stems, pappus present on the disk flowers. 6. 



6. Pappus of the disk flowers 2-5 scale-like bristles. BoUonia. 



6. Pappus of the disk flowers of numerous capillary bristles. 7. 



7. Ray flowers 4-5. 8. 



7. Ray flowers numerous or rarely none. 9. 



8. Flowers in terminal cymose panicles. Sericocarpus 



8. Flowers in crowded clusters forming a spike or thyrsus. Solidago (bicolor). 



9. Pappus in a single series. 10. 



9. Pappus double, the outer series of short bristles. IL 



10. Bracts of the involucre imbricate in several series. Aster. 



10. Bracts of the involucre in but 1 or 2 series. Erigeron. 



11. Ray flowers inconspicuous, white; annuals. Leptilon. 



11. Ray flowers conspicuous. 12. 



12. Rav flowers 25-200, narrow, bracts of the involucre very narrow. Erigeron. 



12. Ray flowers 8-15. 13. 



13. Rays white; leaves lanceolate to oblong, pinnately veined. Doellingeria. 

 13. Ra^'s violet; leaves narrow, one nerved; peduncles covered with bracts. 



lonactis. 



Grindelia Willd. Gum-plant. 



Coarse perennial or biennial herbs with smooth stems, 

 branched above and sometimes woody below. Leaves alter- 

 nate, sessile or clasping, mostly spinulous dentate. Heads 

 either large and solitary at the ends of the branches; involucre 

 hemispherical, its bracts with green points and imbricated in 

 several series; ra}^ and disk flowers yellow. Pappus of 2-8 

 deciduous bristles. Achems short and glabrous. 



