COMPOSITAE (THISTLE FAMILY) 



77 a Plant 1-2 ft. high, cultivated 28. Gaillardia. p 234. 



b Plant 2-10 ft. high, wild or cultivated; leaves smooth 



above 35. Rudbeckia. p 234. 



c Plant 1-7 ft. high, wild or cultivated ; leaves rough 



above 36. Helianthus. p 235 



78 a Leaves more or less toothed 79 



b Leaves entire 81 



79 a Heads 1-2 in. broad, the disk globose 47. Helenium. p 236 

 b Heads 1-2 in. broad, the disk convex 36. Helianthus. p 235 

 c Heads i in. or less broad, the disk not globose 80 



80 a Principal bracts of involucre in i row, sometimes with 



a few shorter outer ones 58. Senecio. p 238 



b Bracts of involucre in several rows, the outer usually 



successively shorter 9. Solid ago. p 228 



8 1 a Heads %-i in. broad 8. Chrysopsis. p 228 



b Heads % in. or less broad 82 



82 a Leaves not linear 9. Solidago. p 228 



b Leaves linear 83 



83 a Irregular or ray flowers usually more numerous than 



the regular flowers 10. Euthamia. p 230 



b Irregular or ray flowers less numerous than the regular 



flowers 8. Chrysopsis. p 228 



84 a Bracts of the involucre in i or 2 rows 85 



b Bracts of the involucre in 3 or more rows 88 



85 a Heads ^4 in. or less broad 17. Leptilon. p 233 



b Heads % in. or more broad 86 



86 a Wild plants 15. Erigeron. p 233 



b Cultivated plants 87 



87 a Leaves ovate-heart-shaped 59. Cineraria, p 238 



b Leaves lanceolate to oblong 28. Gaillardia. p 234. 



88 a Heads arranged in a single, terminal, interrupted spike 



9. Solidago. p 228 

 b Heads not arranged as in a 89 



89 a Pappus of 2 or 4 slender bristles and several scales 



12. Boltonia. p 230 

 b Pappus of numerous capillary bristles 90 



90 a Irregular flowers numerous, shorter than the pappus; 



heads % in. or less broad 17. Leptilon. p 233 



b Irregular flowers usually not shorter than the pappus 91 



91 a Pappus of a single row of capillary bristles 92 



b Pappus of 2 rows of bristles, the outer row shorter, 



sometimes scale-like 93 



92 a Involucre very narrow, less than % in. broad ; heads 



i2-2O-flowered ; irregular or ray flowers 4-7 



13. Sericocarpus. p 230 

 b Plants not completely as in a 14. Aster, p 230 



226 



