Descriptive Flora 



205 



ASTERACEAE. Aster Family. 

 KEY TO ASTERACEAE. 



A. Leaves compound. Page 

 I. Leaves pinnately compound. 



(1) Flowers small, white, in flat-topped 



clusters Achillea— 239 



^. Leaves simple. 



I Leaves netted veined, 

 a. Leaves opposite or clustered, 

 x. Leaves with 1 main vein at base, 

 (a) Flowers yellow or orange, 

 m. Ray flowers all yellow or orange. 



1. Sap milky. 



(1) Plants stemless Taraxacum— 246 



( 2 ) Plants with stems Serinea— 247 



2. Sap not milky, 

 x. Rays 4 — 5. 



(1) Stems coarse, flowers large 



(2) Stems not coarse, flowers Lindheimera— 227 



small • .Calyptrocarpus— 233 



y. Rays 5 — 8, usually 8. 



r. Bracts of the involucre 4, 



very large .Tetragonotheca— 228 



s. Bracts more than 4. 



(m) Leaves rough, petals 



orange Zexmania — 232 



(n) Leaves not rough, petals 

 yellow. 



(1) Stems coarse, hairy. 



o. Leaves crenate Berlandiera — 226 



p. Leaves lobed Engelmannia — 227 



(2) Stems not coarse or 

 hairy (sometimes hairy 



at the nodes) Thelesperma — 235 



z. Rays usually more than 8. 



1. Flowers about across, 



stems weak ...Calyptrocarpus — 233 



2. Flowers over *4" across. 



x. Bracts of the involucre 4, 



very large Tetragonotheca — 228 



