COMPOS1TAE (THISTLE FAMILY) 



93 a Leaves linear; irregular flowers usually violet 



19. lonactis, p 233 

 b Leaves lanceolate to obovate; irregular flowers white 



18. Doellingeria. p 233 



1 VERNdNIA IRON WEED. (V. noveboracensis.) 



2 EUPAT6RIUM. 



1 a Flowers pink or purple; leaves usually in whorls.... 2 

 b Flowers white; leaves usually opposite or alternate.. 3 



2 a Heads in a flattened-topped, cymose panicle 



SPOTTED JOE-PYE WEED. (E. maculatum.) 

 b Heads in a pyramidal panicle 



JOE-PYE WEED. (E. purpureum.) 



3 a Opposite leaves with their bases united around the stem 



THOROUGHWORT. (E. perfoliatum.) 

 b Leaves not with bases united as in a 4 



4 a Leaves linear, opposite or in clusters in the axils 



HYSSOP-LEAVED THOROUGHWORT. (E. hyssopifblium.) 

 b Leaves lanceolate to rounded, not linear 5 



5 a Upper leaves distinctly petioled 6 



b Upper leaves sessile 7 



() a Leaves 3-6 in. long, sharply toothed 



WHITE SNAKEROOT. (E. ageratoldes.) 

 b Leaves 1-3 in. long, bluntly toothed 



SMALL WHITE SNAKEROOT. (E. aromdticum.) 



7 a Leaves tapering at the base 



WHITE THOROUGHWORT. (E. album.) 

 b Leaves more or less rounded at the base 8 



8 a Plant scarcely hairy; leaves 3-6 in. long, long-pointed 



at apex UPLAND BONESET. (E. sessilifblium.) 



b Plants noticeably hairy throughout; leaves 1-4 in. long, 



not long-pointed at apex 9 



9 a Leaves ovate-oblong, 2-4 in. long, usually blunt at apex 



ROUGH THOROUGHWORT. (E. verbenaefblium.) 

 b Leaves roundish-ovate, 1-2 in. long, usually blunt at 



apex. .ROUND-LEAVED THOROUGHWORT. (E. rotundifblium.) 

 c Leaves ovate, 1-4 in. long, usually pointed at apex 



HAIRY THOROUGHWORT. (E. pubescens.) 



3 PIQUfcRI A STEVIA. (P. trinervia*) 



4 AGERATUM AGERATUM. (A. conyzotdes*) 



5 WILLUGBAfcYA CLIMBING HEMPWEED. (W '. scdndens.) 



6 OTH6NNA OTHONNA. (0. capinsis*) 



7 LACINARIA. 



i a Heads M>-i in. broad, is-45-flowered 



LARGE BUTTON SNAKEROOT. (L. scaribsa.) 

 b Heads about "/4 in. broad, 5-i3-flowered 



DENSE BUTTON SNAKEROOT. (L. spicata.) 



227 



