146 



CAEDUACEAE. 



Tribh IV. INULEAE. 



Heads clustered : bracts of the involucre scarious, her- 

 baceous. 



Bracts of the involucre broad, mainly persistent. 



Bracts of the involucre narrow, mainly deciduous. 

 Heads scattered : bracts of the involucre rigid. 



Teibb V. HELIANTHEAE. 



Disk-flowers perfect, but not fruit-producing. 

 Disk-flowers fruit-producing. 



Pappus a mere crown or cap, or of few teeth, awns 

 or bristles. 

 Achenes, at least those of the disk, not com- 

 pressed (except in Phafthnsa) : bractlets 

 mostly concave and clasping. 

 Ray-flowers wanting : bracts of the involucre 



dry. 

 Ray-flowers present : bracts of the involucre 

 herbaceous. 

 Achenes of the disk neither sharp-edged, 

 margined nor winged. 

 Ray-flowers not fruit-producing. 

 Ray-flowers fruit-producing. 

 Achenes of the disk thin-edged, margined or 

 winged. 

 Achenes markedly flattened parallel to the invo- 

 lucral bracts. 

 Pappus of 2 flmbriolate awns, scales or teeth, 



or a mere border or wanting. 

 Pappus of 2-6 awns or teeth, upwardly or 

 downwardly barbed or hispid. 

 Achene beakless : ray-flowers with yellow or 



white Ijgules, or wanting. 

 Achene beaked : ray-flowers with purple or 

 rose ligules. 

 Pappus of numerous scales. 



11. Pluchea. 



12. i'tekocaulon. 



13. Sachsia. 



14. Paethexium. 



15. Melantheea. 



16. boeeichia. 



17. Heliakthtjs. 



18. Ximenesia. 



19. Coreopsis. 



20. Bidens. 



21. Cosmos. 



22. Teidax. 



Teibe VI. HELENIEAE. 



Plant-tissues without oil-glands. 2.3. Flaveeia. 



Plant-tissues, especially the leaves and bracts of the 



involucre, with oil-glands. 24. Pectis. 



Teibb VII. SENECIONEAE. 



Disk-flowers perfect : marginal flowers pistillate. 25. Eeechtites. 



Disk-flowers and marginal flowers perfect. 26. Emilia. 



Teibb VIII. 

 Plants with spine-margined leaves. 



CYNAREAE. 



Ciesum. 



1. VEE.NONIA L. Caulescent herbs. Leaves alternate: blades mostly 

 toothed. Heads not involucrate. Corolla-lobes lanceolate. Anther-appendages 

 lanceolate to oblong. Pappus double, the outer series of scales or stout bristles, 

 the inner of numerous capillary bristles. — Iroxweed. 



Achenes ribbed : corollas 8-12 mm. long. 



Blades of the upper cauline leaves narrowly linear, entire : inner involucral bracts 



1. V. Bloduettii. 



V. gigantea. 

 V. cinerea. 



-6 mm. 

 Blades of the upper cauline leaves not narrowly linear, toothed : 

 inner involucral bracts 3-4 mm. long. 

 Achenes terete or nearly so: corollas about 2 mm. long. 

 c 

 ^^ 1. V. Blodgettii Small. Stems 2-8 dm. tall: leaf -blades oblong to linear, 2-4.5 

 cm. long, entire: involucres fi-7 mm. high; inner bracts oblong or ovate-oblong, 

 acute or acuminate: corolla purple. — Pinelands, L. keys. — [E. K.] 



<'^"'^2. V. gigantea (Walt.) Britton. Stem 9-25 dm. tall: leaf -blades linear to 

 oblong or elliptic, 8-30 cm. long, sharply serrate: involucres 4-5 mm. high; 

 inner bracts narrowly oblong or linear-oblong, obtuse or mucronate. — Ham- 

 mocks, Key West. 



