COMPOSITAE. 349 



Heads in a corymb; 

 pappus a short 



crown. 532. Tanacetum, 381. 



Heads in a raceme 

 or panicle; pap- 

 pus none. 533. Artemisia, 381. 

 Staminate and pistillate flowers in 

 different heads. 

 Pappus capillary; fertile involu- 

 cre not bur-like. 

 Leaves prickly; heads large. 548. Cirsium, 394. 

 Leaves not prickly; heads 

 small. 

 Pappus of staminate flow- 

 ers either club-shaped or 



barbed at the apex. 541. Antennaria, 390. 



Pappus of all the flowers 

 alike and neither club- 

 shaped nor barbed. 542. Anaphalis, 392. 

 Pappus none; fertile involucre 

 bur-like. 

 Bracts of staminate heads 

 separate; bur large, with 



many tegules. 497. Xanthium, 361. 



Bracts of staminate heads uni- 

 ted; bur small, with 1^4 



tegules. 498. Gaertneria, 361. 



Flowers of the heads all perfect and 

 alike. 

 Pappus of separate capillary bristles. 

 Flowers whitish, cream-colored 

 or purplish. 

 Leaves in whorls of 3 to 6. 499. Eupatorium. 361. 

 Leaves alternate or opposite. 



Heads about 10-flowered. 535. Luina, 383. 

 Heads about 40-flowered. 500. Coleosanthus, 362. 

 Flowers yellow or brownish. 



Tegules in 3 or 4 rows. 503. Hoorebekia, 363. 



Tegules in 1 row or nearly so. 

 Involucre hemispheric to 



rotate. 506. Erigeron, 366. 



Involucre campanulate or 

 cylindric. 

 Heads many-flowered. 539. Senecio, 386. 

 Heads 4-7-flowered. 536. Rainiera, 383. 

 Pappus not of separate capillary 

 bristles. 

 Pappus of numerous bristles uni- 

 ted into a ring at the base. 

 Filaments monadelphous be- 

 low. 547. Silybum, 394. 

 Filaments distinct. 



Leaves never prickly. 550. Saussurea, 396. 



Leaves more or less prick- 

 ly. 548. Cirsium, 394. 

 Pappus not of bristles united in a 

 ring. 



