COMFOSITAE. 317 



Heads racemose, spicate, or panicled; pappus none. 



45. Artemisia. 



Tribe 8. SENECIONEAE. 



Leaves all basal; heads on scapes. 



Heads solitary; flowers yellow. 46. Tussilago. 



Heads corymbed; flowers white or purple. 47. Petasites. 



Leaves opposite; rays yellow. 48. Arnica. 



Leaves alternate. 



Flowers white, whitish or pinkish; rays none. 



Marginal flowers pistillate ; disk-flowers perfect. 



49. Erechtites. 

 Flowers all j^erfect. 



Involucre of about 5 bracts; sap milky. 50. Mesadenia. 

 Involucre of about 12 bracts and several smaller outer ones. 



51. Synosma. 

 Flowers yellow ; ray-flowers mostly present. 52. Senecio. 



Tribe 9. CYNAREAE. 



Achenes inserted on the receptacle by their bases, not oblique. 

 Receptacle densely bristly. 



Involucral bracts hooked at the tip; leaves not bristly. 



53. Arctium. 

 Involucral bracts not hooked; leaves bristly. 54. Carduus. 

 Receptacle fleshy, not bristly. 55. Onopordon. 



Achenes obliquely inserted on the receptacle. 56. Centaurea. 



1. VERNONIA Schreb. Iron-weed. 



Involucral bracts with subulate, spreading tips; leaves lanceolate. 



1, V. Noveboracensis. 

 Involucral bracts short, mucronate, or the upper obtuse ; leaves broadly oval 

 or obovate. 2. V. glauca. 



1. Vernonia Noveboracensis (L.) Willd. M. p. 918. Low ground. 



Summer. 



2. Vernonia glauca (L.) Britton. M. p. 919. Woods. Summer. 



2. ELEPHANTOPUS L. 



1. Elephantopus Carolinianus Willd. Elepluint's-foot. M. p. 020. Dry 

 woods. Autumn. 

 Delaware— Chester, Button's Mills (Fu.), Williamson, Dr. Emily G. 

 Hunt (He.), Lansdowne (Pe.), Bridgewater (S. Tr.). Lancaster— Feaeh 

 Bottom (Ca.), McCall's Ferry (Cr.), Susquehanna Valley (Le.). 

 Nerv Castle — Common. 



3. SCLEROLEPIS Cass. 



1. Sclerolepis uniflora (Walt.) Porter. M. p. 920. Pine-barrens. Sum- 

 mer. 

 Burlington — (Quaker Bridge. Cape May — Woodbine (Br.), Cape May 

 (Te.). Atla^itic-UsLmmontoTi, Egg Harbor (U. C. S.) (Sts.). 

 New Castle — Near Sassafras X-roads, Commons. 



4. EUPATORIUM L. Thoroughwtort. 

 ^Leaves alternate, pinnatifid into filiform segments. 



1. E. capillifolium. 



