ASTER FAMILY 247 



m. Rays large and broad, 4-5 ; pappus 



of a few awns CRASSINA 



n. Rays small, 2-5 ; pappus none MADIA 

 (y) Rays 10 or more 



m. Pappus none; leaves 6-12 in. long BALSAMORRHIZA 

 n. Pappus present 



(m) Inner involucral scales united 

 into a cup ; pappus of 2 awns 

 or scales THELESPERMA 



(n) Inner scales not united into a cup 

 r. Pappus of 2-6 barbed awns BIDENS 

 s. Pappus awns not barbed 

 (r) Rays less than 1 in. long; 

 involucral scales in 2 dif- 

 ferent rows COREOPSIS 

 . 



(s) Rays an inch or more long 

 h. Leaves opposite ; pappus a 



crown or 1-3 teeth HELIOPSIS 

 i. Leaves alternate ; pappus 



a crown of 5-10 teeth WYETHIA 

 (b) Rays neutral, i. e., without a style 

 x. Disk globoid, conic or cylindric 



(x) Pappus a 4-toothed crown, or if 



none, the disk purple-black 

 m. Achenes flattened RATIBIDA 



n. Achenes 4-angled RUDBECKIA 



(y) Pappus inconspicuous or none; disk 



yellow GYMNOLOMIA 



y. Disk convex to flat 



(x) Pappus of 2 awns only HELIANTHUS 



(y) Pappus of scales and 2 awns, or of 



scales alone HELIANTHELLA 



b. Receptacle not chaffy 

 (1) Pappus hairy 

 (a) Rays yellow 

 x. Leaves opposite 



(x) Rays 1-4 cm. long ARNICA 



(y) Rays 2-4 mm. long HAPLOESTHES 



y. Leaves alternate 



(x) Involucral bracts equal, in 1 row, 



often with small ones at base SENECIO 



