COMPOSITE FAMILY 24I 



I. Radiate Compositae. 

 (Heads with rays.) 



A. Rays "blue, purple, or white. 



Leaves finely cut into many small lobes; rays 

 white. 



Heads solitary; annual 33. Anthemis, p. 261 



Heads clustered; perennial 34. Achillaea, p. 261 



Leaves entire or merely toothed or with very few 

 lobes, rays variously colored. 

 Pappus of 3 to 12 scales or awns. 

 Bracts very acute. 



Heads small ; rays white 29. Rigiopappus, p. 259 



Heads Y4 in. high; rays saffron-color Hulsea heterochroma, p. 260 



Bracts obtuse, enfolding the outer akenes. . .Hemitonia douglasii, p. 258 

 Pappus of numerous bristles. 



Plant white-woolly 10. Corethrogyne, p. 247 



Plant glabrous or hairy, not woolly. 



Disk-flowers and ray-flowers both white... 11. Sericocarpus, p. 248 

 Disk-flowers yellow. 



Bracts of the involucre in 2 or more 

 series, mostly unequal; style-appen- 

 dages acute 12. Aster, p. 248 



Bracts in 1 or 2 series, mostly equal; 



style-appendages obtuse 13. Erigeron, p. 250 



B. Rays yellow or orange-color. 



Pappus of numerous slender bristles. 



Bracts of the involucre unequal, in 2 or more 

 rows, the outer often shorter; pappus rigid. 

 Heads many, small (scarcely Y% in. high, in- 

 cluding rays) 4. Solidago, p. 245 



Heads few, larger. 



Involucre-bracts very unequal, of 4 or more 

 lengths, the outer regularly shorter. 



Akenes very pubescent 3. Chrysopis, p. 245 



Akenes glabrous 8. Hazardia, p. 247 



Involucre-bracts of nearly equal length... 5. Haplopappus, p. 246 

 Bracts of the involucre equal (often a few mi- 

 nute outer ones at base) ; pappus soft, 

 hair-like. 



Leaves opposite 38. Arnica, p. 263 



Leaves alternate 39. Senecio, p. 264 



Pappus of 2 to 12 scales or awns, or wanting. 



Bracts of the involucre each enveloping or 



wrapped about an outer akene, so that on 



pulling off a bract the akene comes away 



with it. 



Outer akenes and their bracts with narrow 



backs 24. Madia, p. 257 



Outer akenes and their bracts with broad 

 rounded backs. 



Plant not 6 in. high 25. Hemizonella, p. 258 



Plant 1 ft. or more high 26. Hemizonia, p. 258 



