636 COMPOSITAE 



Pa. Near Tullytown, Bucks Co. 



A rare and local species, apparently localized in the lower Dela- 

 ware valley. 



4. S. pauperculus Michx. (S. Balsamitae Muhl.). In dry or rocky 



soil: N. S. to N. Car., west to Wash., B. Col., Tex. and 



Neb. 



Conn. Known only from Washington, Woodbury, Oxford and 

 Southbury, rare. 



N.Y. TodtHill, S. I. 



N. J. Somerset, Essex and Hunterdon counties, increasing north- 

 ward. 



Pa. Monroe, Northampton, Lehigh, Bucks, Montgomery, Dela- 

 ware and Chester counties. 



Tertiary, 0: Cretaceous, 0: Older Formations, increasing west- 

 ward. 117-220 days. Sea level-3,8oo ft. 



5. S. Smallii Britton. Meadows and thickets: S. E. Pa. to Fla. 



and Ala. 



Pa. Serpentine barrens, Delaware county. 



6. S. aureus L. In swamps and wet meadows: Newf. to Fla., 



west to Ont., Mo. and Tex. 



Common throughout the range except the pine-barrens, there rare, 

 decreasing southward. 



7. S. vulgaris L. In cultivated ground and waste places: Newf. 



and Hudson Bay to Va., west to Mich, and S.Dak. Also 

 on the Pacific Coast. 



Rare as an occasional weed in our area. 



Senecio viscosus L., S. Jacobaea L. and 5. sylvaticus L. are all sometimes adventive. 



51. Arnica L. 

 1 . A. acaulis (Walt.) B. S. P. In low woods: Del. and southern Pa. 

 Known only from near Barnsley, Chester Co., Pa., in our area. 



Tribe 9. Cvnareae 



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

 Receptacle densely bristly. 

 Filaments separate. 



Involucral bracts hooked at the tip; leaves not bristly. 52. Arctium. 

 Involucral bracts not hooked at the tip; leaves bristly. 



Pappus-bristles plumose. 53. Cirsium. , 



