778 



COMPOSITAE (COMPOSITE FAMILY) 



Fertile involu«re armed with 2 or more rows of spines or these 



irregularly distributed 41. Franseria. 



Bracts of staminate involucre distinct ; fertile involucre horned in 



fruit and very prickly 42. Xanthmm. 



§ 2. Bays present, i.e. 



the marginal floioers 

 corollas. 



or some of them ivith strap-like 



I 



* Pappus of capillary bristles, at least in the disk-flowers; ray -flowers pistillate I. 



..... 74. Tkissilago. 



I 



75. Petasiies. 



23. Erigeron. 



75. PetasUes. 



15. SoUdago. 



Rays occupying several rows. 

 Kays yellow ........... 



Rays white or purpUsh. 



Leaves cordate 



Leaves not cordate ......... 



Rays in one marginal row m. 

 m. Ravs not yallow. 



Upper part of stem bearing ovate or lanceolate phyllodia . . 

 Phyllodia none. 



Kays and disk-flovers similarly colored 



Rays and disk-flowers of contrasting colors. 



Rays 4 or 5 24. Sericocarptts. 



Rays numerous. 

 Involucral bracts subequal, narrow, chiefly in 1 series 

 Involucral bracts imbricated in several mostly unequal series 

 m. Rays vellow n. 



n. Pappus (at least in the disk-flowers) double, the outer short and 

 minute. 



Ray-flowers with pappus of capillary bristles 



Ray-flowers with coroniform pappus 



n. Pappus simple. 



Leaves opposite 76. Arnica. 



Leaves alternate. 

 Involucral bracts equal and in 1 row (though often calyculate) 

 Involucral bracts imbricated in several series. 



Heads 3-5 cm. in diameter 



Heads 2 cm. or less in diameter. 

 Pappus of several very narrow scales rather than truly 

 capillary bristles. 

 Pappus of disk-flowers nearly or quite as long as the 



corolla 12. 



Pappus of disk-flowers much shorter than the corolla . 11. 

 Pappus-bristles hair-like. 



Pappus-bristles equal 15. Solidago. 



Pappus-bristles unequal 17. Aplopappvs. 



* * Pappus a circle of awns or rigid bristles at least in the disk- 

 flowers 10. Grindelia. 



23. 

 22. 



14. 

 13. 



Erigeron. 

 Aster, 



Chrysopsis. 

 ffeterotheca. 



79. 

 31. 



Senecio. 

 Inula. 



A mphiachyris. 

 Gutierrezia. 



*** Pappus a circle of chaffy scales dissected into bristles 

 * * * * Pappus a circle of thin chaffy scales or short chaffy bristles o. 



66. I>yssodia. 



0. 



o. 



Receptacle deeply honeycombed 

 Receptacle not deeply honeycombed, naked. 

 Receptacle flattish ; heads small, few-flowered 

 Leaves serrate, the lower heart-shaped 

 Leaves entire, linear, never cordate 

 Receptacle elevated, strongly convex ; heads 



Scapose 



Leafy-stemmed ; leaves decurrent 

 Receptacle not deei)ly honeycombed, chaff'}'. 

 Heads less than 1 cm. in diameter . 

 Heads more than 1 cm. in diameter 



57. Balduina. 



many-flowered. 



16. 

 11. 



63. 

 64. 



Brachychaeta. 

 Gutierresia. 



Actinea. 

 Helenium. 



59. Galinsoga. 

 65. Gaillardia. 



* * * * * Pappus none, or a cup or crown, or of 2 or 3 awns, teeth or chaffy scales corresponding 

 with the edges or angles of the achene, often with intervening minute bristles 

 or scales. 



-t- Receptacle naked p. 

 p. Achenes flattened. 



Achenes wing-margined ; pappus present 21. Boltonia. 



Achenes marginless ; pappus none 19. Bellis. 



p. Achenes terete or prismatic. 



Receptacle conical .69. Matricaria. 



Receptacle flattish. 



Heads verv small ; rav-flowers mostly 1 60. Fhiveria. 



Heads rather large; r.ays numerous 70. Chrynanthemum 



p. Achenes fusiform ; pappus of few scales, usually alternating with awns 20. Chaetopappa. 



+- -K Rkcei'taoi.e chakfv q. 



q. Rays neutral (rarely pistillate but sterile); the disk-flowers perfect 

 and fertile. 



