COMPOSITAE. 351 



short chaffy teeth or 

 awns. 



Rays pistillate and fer- 

 tile. 519. WYETHIA, 376. 

 Rays neutral. 520. HELIANTHUS, 377. 

 Receptacle not chaffy. 

 Tegules in one row. 



Akenes obpyramidal ; re- 

 ceptacle naked. 526. HELENIUM, 379. 

 Akenes linear, more or less 

 4-angled ; receptacle 

 beset with bristly 

 points. 



Tegules distinct. 522. BAERIA, 377. 



Tegules united into a 



cup. 523. ERIOPHYLLUM, 378. 



Tegules in more than one 



row. 



Tegules in many rows. 501. GRINDELIA, 362. 



Tegules in two or three 



rows. 

 Receptacle bristly; 



pappus present. 525. GAILLARDIA, 378. 



Receptacle naked; pap- 

 pus present or 

 none. 



Pappus of 4 or 5 trun- 

 cate scales, erose 

 or lacerate at the 

 tip or nearly en- 

 tire. 524. HULSEA, 378. 

 Pappus none. 521. JAUMEA, 377. 

 Pappus of capillary bristles. 

 Ray-flowers not yellow. 



Tegules in 1 or 2 series, nar- 

 row; ray-flowers usually 



narrow and numerous. 506. ERIGERON, 366. 



Tegules in 2-5 series; ray- 

 flowers broader, less 

 numerous. 



Involucre narrow, with 

 rigid bracts; ray- flowers 



white, 4 or 5. 507. SERICOCARPUS, 369. 



Involucre turbinate or 

 hemispheric; ray- 

 flowers more than 5. 



Stems scape-like. 508. OREOSTEMMA, 370. 



Stems leafy. 



Tegules dry and 

 chartaceou s, 

 closely appress- 



ed. 509. BUCEPHALUS, 370. 



Tegules more or less 

 herbaceous and 



spreading. 510. ASTER, 371. 



Ray-flowers yellow. 



Pappus double, the outer row 

 very short. 502. CHRYSOPSIS, 363. 



