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14. Amphiachyris. Heads small: ray-flowers 5 to 10, with coroniform pappus: 
disk-flowers infertile, with pappus of several bristle-like scales: annuals with very 
narrow leaves. 
15. Grindelia. Heads large, many-flowered: flowers all fertile; pappus of 2 to 8 
rigid caducous awns: coarse herbs with toothed leaves. 
+ + Pappus of numerous slender or capillary bristles. 
++ Pappus double. 
16. Heterotheca. Resembling Chrysopsis, but achenes of the ray thicker than 
those of the disk and without pappus or nearly so. 
17. Chrysopsis. Heads many-flowered, with numerous rays: outer pappus of 
very small chaffy bristles, much shorter than the inner of copious capillary bristles. 
18. Xanthisma. Heads many-flowered, radiate: receptacle alveolate-fimbrillate: 
pappus of 10 to 12 rigid bristles becoming chaffy below and longer than the disk- 
corolla, a8 many more one-half shorter, and usually 5 still smaller and shorter ex- 
ternal ones. 
++ ++ Pappus simple. 
19. Bradburia. Heads with about 12 fertile ray-flowers and about as many in- 
fertile disk-flowers: involucre campanulate: pappus of the ray of numerous unequal 
rigid capillary bristles little longer than the 3-angled achene: of the abortive disk- 
achenes of very few (usually 2) bristles,which are somewhat chaffy at base. 
20. Aplopappus. Heads many-flowered, many-radiate: involucre hemispherical : 
pappus of many unequal bristles. 
21. Bigelovia. Heads 3 or 4-flowered; rays none: receptacle awl-shaped: pappus 
a single row of capillary bristles. 
22. Solidago. Heads few to many-flowered; rays 1 to 6: pappus of numerous 
slender and equal capillary bristles. 
* * Ray flowers white, blue, or purple, never yellow. 
+» Pappus of both disk and ray none or coroniform. 
4+ Involucre broad, many-flowered: rays numerous, fertile, conspicuous. 
93. Bellis. Involucral bracts equal: achenes marginless,flattened: pappus none. 
24, Aphanostephus. Outerinvolucral bracts shorter: achenes prismatic: pappus 
coroniform. 
++++ Involucre narrower and flowers less numerous. 
25. Keerlia. Involucral bracts oblong, imbricated in few series of unequal length: 
rays 5 to 15: pappus minute and coroniform or evanescent from the mature achenes. 
++ Pappus usually with awns. 
26. Cheetopappa. Achenes fusiform, without wings or callous margins: pappus 
of 5 or fewer thin scales and alternating awns: receptacle flat or nearly so. 
27. Dichetophora. Involucral bracts somewhat uniserial and equal: achenes sur- 
rounded by an almost orbicular firm wing, its edge and the body of the achene 
glochidiate-hispid: pappus of 2 divergent awns and several minute scales: recepta- 
cle strongly convex: low annual. 
28. Boltonia. Involucre imbricated and appressed: achenes obovate, very flat, 
with callous or winged margin, glabrous or minutely hispidulous: pappus of several 
short chaffy bristles and usually 2 (rarely 3 or 4) elongated rigid awns: receptacle 
strongly convex: leafy-stemmed perennials, 
+++ Pappus of numerous long and capillary bristles: receptacle ftat. 
++ Pappus of the ray-flowers none or a mere vestige. 
29. Psilactis. Involucre hemispherical; its bracts imbricated in 2 or 3 series (with 
herbaceous tips): ray-flowers often sterile but style-bearing: achenes pubescent and 
narrow ; those of the ray sometimes with an obseure ring in place of pappus; those 
of the disk with a single series of soft capillary bristles. 
