634 COMPOSITAE 



Involucre of about 5 bracts; sap milky. 48. Mesadenia. 

 Involucre of about 12 bracts and several smaller outer 



ones. 49. Synosma. 



Flowers yellow; ray-flowers mostly present. 50. Senecio. 



Leaves opposite; rays yellow 51. Arnica. 



45. Tussilago [Tourn.] L. 



1. T. Farfara L. In moist soil or along roadsides: N. S. and 



N. B. to Mass., N. Y. and Minn. Native of Europe. 

 Locally abundant as a weed, often wanting. 



46. Petasites [Tourn.] Mill 



Flowers whitish, the pistillate radiate. I. P. palmata. 



Flowers all rayless, purple. 2. P. Petasites 



i. P. palmata (Ait.) A. Gray. In swamps and along streams :Newf. 

 to Alask., and B. Col., south to Conn., N. Y., Wise, and Cal. 

 Localized in our area near Salisbury, Conn., at elevations of about 

 1,500 ft. 



2. P. Petasites (L.) Karst. In cultivated and waste ground: 



Mass., Conn, and E. Pa. Native of Europe. 

 Rare as a weed in Conn, and Pa. 



47. Erechtites Raf. 



1. E. hieracifolia (L.) Raf. In woodlands, thickets and waste 

 places: Newf. to Fla., west to the N. W. Terr., Neb., Kan. and 

 La. Also in Mex. and S. Am. 



Common, always as a weed, in most parts of our area. 



48. Mesadenia Raf. 



Leaves green both sides, angulate-dentate. 1. M, reniformis. 



Leaves glaucous beneath, green above, angulate-Iobed. 2. M. atriplicifolia. 



1. M. reniformis (Muhl.) Raf. In woods: N. J. and Pa. to 



Minn., south to N. C. and Tenn. 



Known in our area, only from Camden Co., N. J., and Northamp- 

 ton Co., Pa. 



2. M. atriplicifolia (L.) Raf. In woods: western Ont. to Minn., 



south to Fla., Mo. and Kan. 



Known in our area, only from the drainage of the Delaware River 

 in N. J. and Pa., not common. 



