56 COMPOSITE. 



squamellae, which are shorter than and concealed by the bristly hairs of the akene. Low 

 annual. 



42. BOLTONIA. Involucre imbricated, appressed ; the outer bracts shorter. Style-append- 

 ages short-lanceolate. Akenes obovate, very flat, with callous or winged margin, glabrous 

 or minutely and sparsely hispidulous. Pappus of several short-setulose squamellse, and usu- 

 ally of 2 (rarely 3 or 4) elongated rigid awns. Leafy-stemmed perennials. 



* * * * Pappus, a single series of long awns (or only 2 or 3) or of coarse and rigid bristles, 

 or in the (fertile and conspicuous) ray reduced to squamellas or palete : receptacle flat. 



43. TOWNSENDIA. Involucre broad, many-flowered, imbricated ; the bracts lanceolate, 

 with scarious margins and tips, outer usually shorter and inner more membranaceous. Re- 

 ceptacle broad, merely areolate. Style-appendages lanceolate. Akenes obovate or oblong, 

 much compressed, and with thickish or mostly callous margins, those of the ray sometimes 

 triangular. Awns or bristles of the pappus from hispidulo-scabrous to barbellulate. 

 ***** Pappus of numerous capillary bristles, at least in the disk, with or without a 



short setulose or squamellate outer series : receptacle flat or barely convex : akenes mostly 

 compressed. 

 -i— Style-appendages of disk-flowers comose-bearded : anthers tipped with slender-subulate 

 appendages, as in Lessingia : rays neutral. 



44. CORETHROG-YNE. Involucre broad, imbricated; its bracts with herbaceous or 

 green tips. Receptacle f oveolate, rarely with a few chaffy bracts toward the margin. Style- 

 appendages short-lanceolate, dorsally beset with long hispid hairs forming a bearded tuft. 

 Akenes of the ray abortive and with reduced scanty pappus or none; those of the disk 

 narrow, silky-villous or pubescent, few-nerved; their pappus of rather rigid and unequal 

 capillary bristles. 



H— -i— Style-appendages merely hispidulous or puberulous, not comose. 

 ++ Pappus none or a mere vestige in the ray-flowers : these often sterile but styliferous. 



45. PSILACTIS. Involucre hemispherical ; its bracts imbricated in 2 or 3 series, and with 

 herbaceous tips, or the outer herbaceous. Rays in a single series, sometimes short. Akenes 

 pubescent, narrow ; those of the ray sometimes with an obscure ring in place of pappus ; 

 those of the disk bearing a single series of soft capillary bristles. Leafy-stemmed annuals. 



++ -H- Pappus present and mostly similar in ray and disk : flowers (with rare exceptions) 

 all fertile. Genera of difficult limitation. 



46. EREMIASTRUM. Involucre broad, many-flowered, of numerous lax and linear 

 bracts, all as long as the disk and nearly in a single series, herbaceous, with hyaline-scarious 

 and erose-fimbriate margins, their back setose-hispid. Receptacle broad and flat. Rays 

 numerous in a single series; ligules broad, their base and tube villous-barbate. Style-ap- 

 pendages lanceolate. Akenes obovate-oblong, compressed, 2-nerved. Pappus of rather few 

 very unequal and somewhat rigid bristles ; the stronger ones considerably shorter than the 

 disk-corolla and only 8 to 12 ; the smallest and outermost setulose and scarcely longer than 

 the hirsute pubescence of the akene, sometimes coalescent irregularly at base ; intermediate 

 ones of various length and more numerous. Depressed winter-annual. 



47. SERIOOCARPUS. Involucre several-flowered, narrow, of closely imbricated and 

 appressed whitish and coriaceous or cartilaginous bracts, with green-nerbaceous abrupt and 

 looser or spreading tips. Receptacle small, foveolate. Corollas both of ray and disk white 

 or cream-color ; the rays seldom over 5 or 6, rather broad ; disk-corollas (8 to 20) with 5-cleft 

 limb. Style-appendages lanceolate-subulate. Akenes narrow, little compressed, 2-nerved", 

 sericeous-pubescent. Pappus of numerous unequal scabrous bristles. Leafy-stemmed 

 perennials. 



48. ASTER. Involucre from hemispherical to campanulate, sometimes oblong or turbinate, 

 imbricated in several or few series of unequal bracts, mostly in part herbaceous. Rays 

 numerous, not very narrow. Style-appendages from slender-subulate to ovate-acute, com- 

 monly lanceolate. Akenes mostly compressed, 10-4-2-nerved, and the pappus mostly simple 

 and copious, rarely distinctly double. Leafy-stemmed herbs, the greater part perennials. 



49. ERIGERON. Differs from Aster in the more naked-pedunculate heads, simpler in- 

 volucre of narrow and erect equal bracts, which are never coriaceous, nor foliaceous or with 

 distinct herbaceous tips, narrower and usually very numerous rays often occupying more 



