COMPOSITAE (THISTLE FAMILY) 



45 a Leaves entire 41. Zinnia, p 235 



b Leaves pinnately compound 46 



46 a Leaflets ovate 43. Dahlia, 



b Leaflets linear 42. Cosmos, 



47 a Ray flowers white or pink 48 



b Ray flowers yellow or yellowish 53 



48 a Leaves pinnately compound, the segments linear 



42. Cosmos, p 235 

 b Leaves simple 49 



49 a Leaves ovate or triangular-ovate, usually rounded at 



the base 50 



b Leaves linear to lanceolate, narrowed at the base 51 



50 a Wild herb; heads about }4 in. broad 



45. Galinsoga. p 236 



b Cultivated herb ; heads 1-3 in. broad 46. Arctotis. p 236 



51 a Ray flowers 4-8, pink, rarely white.. 40. Coreopsis, p 235 

 b Ray flowers several 52 



52 a Ray flowers whitish; wild herbs.... 33. Eclipta. p 234. 

 b Ray flowers purple to crimson 34. Brauneria. p 234 



53 a Outer bracts of involucre leaf-like, much larger than 



the inner 54 



b Outer bracts of involucre usually conspicuously smaller 



than the inner 55 



54 a Achenes crowned by a pappus of 2-4 stiff, barbed awns 



44. Bidens. p 236 

 b Achenes not crowned by a pappus.. 30. Polymnia. p 234 



55 a Heads Vi-Vz in. broad; achenes not crowned by a pap- 



pus 33. Eclipta. p234 



b Heads Vi in. or more broad 56 



56 a Receptacle of head conic or convex 57 



b Receptacle of head more or less flat 58 



57 a Bracts of involucre in 1-3 rows; achenes sometimes 



crowned by a pappus of 2-4 teeth 32. Heliopsis. p 234 

 b Bracts of involucre in 3 or more rows; achenes usually 



crowned by scales or awns 36. Helianthus. P 235 



58 a Achenes crowned by a pappus of 2-4 stiff, barbed awns 



44. Bidens. p 236 

 b Achenes not crowned by a pappus of barbed awns.... 59 



59 a Bracts of the involucre in 2 rows united at the base 



40. Coreopsis, p 235 

 b Bracts of the involucre in several rows, not united at 



the base 36. Helianthus. p 235 



60 a Leaves pinnatifid, pinnately compound, or dissected 61 



b Leaves entire, toothed, or incised 71 



61 a Heads %-% in. broad 62 



b Heads Vz in. or more broad 63 



224 



