SUNFLOWER FAMILY. 



4«y 



B. Receptacle without bracts (not chaffy); involucral bracts many (except 



no. 75); perennials or annuals. 

 Pappus present; achenes naked. 

 Bracts of the involucre scarious; herbage woolly. 



Flowers all fertile, perfect and pistillate in the same head 



72. Gnaphalium, p. 560. 



Flowers dioecious 73. Anaphalis, p. 552. 



Bracts of the involucre dry but not scarious; herbage not woolly 



74. Pluchea, p. 552. 

 Pappus none; achenes bearing stipitate glands; leaves broad, woolly 

 beneath 75. Adenocatjlon, p 563. 



Tribe 10. Astereae. Aster Tribe. 



Annual or perennial herbs or shrubs, with bland watery juice, 

 scentless herbage (the foliage sometimes gummy or resinous) and 

 alternate leaves. Receptacle naked. Bracts of the involucre com- 

 monly well imbricated. Disk-flowers yellow (except in some 

 Lessingias and Pentachsetas), perfect in all ours except Baccharis. 

 Rays present or absent. Anthers not caudate at base. Pappus of 

 awns or bristles (except Bellis). 



A. Flowers of both disk and ray yellow (except in Pentachaeta) ; rays present 



(except in no. 83 and one species of nos. 78, 80 and 82). 



Pappus of several short scales; heads very small ... 76. Gutierrezia, p. 553. 

 Pappus of several caducous awns or bristles; heads large and very 

 gummy; involucral bracts often squarrose; leaves not narrow, mostly 



serrate; perennial herbs 77. Grindelia, p. 554. 



Pappus of persistent bristles. 

 Bristles 3 to 5 (sometimes obsolete); low annuals with filiform steins and 



leaves 78. Pentachaeta, p. 556. 



Bristles many. 



Ray-achenes without pappus or the pappus a reduced crown 



79. Heterotheca, p.5 66. 

 Ray-achenes (when present) with pappus like that of disk. 

 Pappus often of 2 kinds; the inner capillary, the outer very short 



and scale-like or obsolete 80. Chrysopsis, p. 557. 



Pappus of one kind. 

 Evergreen shrubs. 

 Heads solitary at the ends of the branches; pappus permanently 



white 81. 8tenotus, p. 558. 



Heads in cymoseor corymbose clusters; pappus in age reddish. . . 



82. Ericameria, p. 559. 

 Suffrutescent or herbaceous plants; heads in corymbs or panicles. 

 Rays none; corolla throat ventricose . . . .83. Isocoma, p. 559. 

 Rays present; corolla not ventricose . . . 84. Solidago, p. 560. 



B. Flowers yellow, white, or purple; rays none, but the outer corollas often 



enlarged and more deeply cleft on the inner side. 



Heads small, turbinate or campanulate; pappus present, its bristles com- 

 monly numerous and reddish brown in age; annuals 



85. Lessingia, p. 561. 



C. Flowers of the disk yellow (sometimes changing to purple); rays never 



yellow, always present (but so inconspicuous as to appear wanting 

 in one species of Aster and of Erigeron). 



Pappus none; heads on scape-like peduncles; rays white or pink-tinged; 

 ours perennial herb 86. Bellis, p. 564. 



