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. Eeiophyllum, 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 

 chartaceous, 

 closely appress- 



ed. 509. Eucephalus, 370. 



Tegules more or less 

 herbaceous and 



spreading. 510. Aster, 371. 



Ray-flowers yellow. 



Pappus double, the outer row 

 very short. 502. Chrysopsis, 363. 



