COMPOSITAE. 



349 



Heads in a corymb; 

 pappus a short 

 crown. 532. 



Heads in a raceme 

 or panicle; pap- 

 pus none. 533. 

 Staminate and pistillate flowers in 



different heads. 



Pappus capillary; fertile involu- 

 cre not bur-like. 

 Leaves prickly; heads large. 

 Leaves not prickly; heads 



small. 



Pappus of staminate flow- 

 ers either club-shaped or 

 barbed at the apex. 541. 



Pappus of all the flowers 

 alike and neither club- 

 shaped nor barbed. 542. 

 Pappus none; fertile involucre 



bur-like. 



Bracts of staminate heads 

 separate; bur large, with 

 many tegules. 497. 



Bracts of staminate heads uni- 

 ted; bur small, with 1-4 

 tegules. 498. 



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. 

 Leaves alternate or opposite. 



Heads about 10-flowered. 535. 

 Heads about 40-flowered. 500. 

 Flowers yellow or brownish. 



Tegules in 3 or 4 rows. 503. 



Tegules in 1 row or nearly so. 

 Involucre hemispheric to 



rotate. 506. 



Involucre campanulate or 



cylindric. 



Heads many-flowered. 539. 

 Heads 4-7-flowered. 536. 

 Pappus not of separate capillary 



bristles. 



Pappus of numerous bristles uni- 

 ted into a ring at the base. 

 Filaments monadelphous be- 

 low. 547. 

 Filaments distinct. 



Leaves never prickly. 550. 



Leaves more or less prick- 

 ly. 548. 

 Pappus not of bristles united in a 

 ring. 



TANACETUM, 381. 

 ARTEMISIA, 381. 



548. CIRSIUM, 394. 



ANTENNARIA, 390. 

 ANAPHALIS, 392. 



XANTHIUM, 361. 

 GAERTNERIA, 361. 



499. EUPATORIUM. 361. 



LUINA, 383. 

 COLEOSANTHUS, 362. 



HOOREBEKIA, 363. 



ERIGERON, 366. 



SENECIO, 386. 

 RAINIERA, 383. 



SILYBUM, 394. 

 SAUSSUREA, 396. 

 CIRSIUM, 394. 



