KEY FOR JUNE TO NOVEMBER 



276 a Outer bracts of the involucre much larger than the 



inner ones 277 



b Outer bracts of the involucre not larger than the inner 



ones 278 



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



Bidens. p 236 

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



278 a Receptacle of head conic or convex 279 



b Receptacle of head more or less flat 280 



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



crowned by 2-4 teeth Heliopsis. 234 



b Bracts of the involucre in several rows; achenes usually 



crowned by 2 scales or awns Helianthus. p 235 



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



Bidens. p 236 

 b Achenes not crowned as in a 281 



281 a Bracts of the involucre in 2 rows and united at the base 



Coreopsis, p 235 

 b Bracts of the involucre in several rows not united at 



the base Helianthus. p 235 



282 a Leaves pinnately divided or dissected 283 



b Leaves toothed or entire 285 



283 a Heads %-% in. broad Tanacetum. p 237 



b Heads Vz in. or more broad 284 



284 a Heads 2-4 in. broad; ray flowers 6-10, often drooping 



Rudbeckia. p 234 

 b Heads 2 in. or less broad; ray flowers 10-40. A nthemis. p 236 



285 a Heads 2-4 in. broad 286 



b Heads 2 in. or less broad 288 



286 a Plant 2-6 ft. high; leaves 4-20 in. long, broadly oblong 



Inula. p 234. 

 b Plants not completely as in a 287 



287 a Plants 1-2 ft. high; leaves smooth on upper side 



Rudbeckia. p 234 

 b Plants 1-7 ft. high; leaves rough on upper side 



Helianthus. p 235 



288 a Heads 1-2 in. broad; disk globose or convex 289 



b Heads i in. or less broad ; disk not globose 290 



289 a Disk of head globose Helenium. p 236 



b Disk of head convex Helianthus. p 235 



290 a Leaves linear 291 



b Leaves not linear 292 



291 a Ray flowers usually more numerous than the disk 



flowers Euthamia. p 230 



b Ray flowers not more numerous than the disk flowers 



Chrysopsis. p 228 



