COMPOSITAE 



B'. Principal involucral bracts in 3 or more series, unequal or 

 subequal. 

 Heads small, not over 1cm. wide, usually numerous; outer 

 phyllaries slightly if at all herbaceous tipped, much shorter 



than the inner 4 . 



Heads larger, about 3 cm. wide, solitary or few at tips of 

 stems and brs. ; outer phyllaries herbaceous-tipped, eq- 

 ualling or surpassing the inner 12 . 



B'B'. Principal involucral bracts in a single series, sometimes with a 



few small outer ones added. 



Stem lvs. with conspicuously enlarged sheathing petioles, or 



else (L. kaempferi) plant subscapose and basal lvs. 



reniform; the blade broader than long: heads large; the 



disk 1.2-2.5 cm. high 35. 



Stem lvs. not with sheathing petioles; if plant subscapose 

 the basal lvs. obovate or oblong: heads smaller; the disk 



0.5-1.5 cm. high 34. 



A'A'. Pappus not of fine hair-like bristles only, sometimes wanting. 



C. Involucral bracts in a single series, united essentially to 



apex into a tube or cup: lvs. pinnately divided, 



bearing internal glands containing a strong-scented oil . . 28 . 



C'C. Involucral bracts not in a single series, or if so, not 



united into a tube or cup: lvs. otherwise. 



D'. Outer achenes strongly incurved, muricate, heteromor- 



phous: receptacle naked; disk fls. sterile 36. 



D'D'. Outer achenes not incurved and muricate: receptacle 

 (except in Chrysanthemum) chaffy or with chaff- 

 like or bristle-like outgrowths from the margins 

 of the areolae; disk fls. not sterile. 

 E\ Pappus of about 10 awned scales; achenes 5- 



ribbed 27 . 



E'E'. Pappus not of awned scales; achenes not 5- 

 ribbed. 

 F\ Outer involucral bracts few (about 5), wide- 

 spreading, linear-spatulate, hispid- 

 glandular; rays very short, the heads 

 only about 1 cm. wide, or less: pappus 



none 18 • 



F'F'. Outer involucral bracts not as above; rays 

 mostly conspicuous, over 1cm. long: 

 pappus usually present. 

 G'. Involucre distinctly double; the outer of herbaceous but narrow 

 bracts; the inner of flat membranous scales. 



Achenes beaked 26 . 



Achenes not beaked although sometimes slender above. 

 Pappus of short teeth (not retrorsely barbed) or wanting. . 23. 



Pappus of 2-4 retrorsely barbed stiff awns 25. 



G'G'. Involucre not double. 



H' Ray corollas sessile, indurated and persistent on the achenes. 

 Disk achenes compressed, very flat: lvs. entire: involucre 



strongly graduated 16 • 



Disk achenes strongly thickened: lvs. toothed: involucre 



slightly if at all graduated 17. 



392 



Solidago 



Inula 



Ligu laria 



Senecio 



Tagetes 



Calendula 



Gaillardia 



Sigesbeckia 



( 'osmos 



Coreopsis 

 Bidens 



Zinnia 

 Heliopsis 



