346 CRUCIFERAE 



23. Draba [Dill.] L. 



Petals deeply 2-cleft. I . D. verna. 



Petals entire, toothed or emarginate. 2. D. caroliniana. 



i. D. verna L. In fields: common throughout U. S. and Canada, 

 except in the extreme north. Naturalized from Europe. 

 Common in the south, decreasing northward. 



2. D. caroliniana Walt. In sandy fields: Mass. to Ont., Minn., 



Neb., Ga. and Ark. 



Conn. Rare along the coast, decreasing inland, and wanting in the 

 north. 



N. Y. Reported from near Ridgewood, L. I. and Rossville, S. I. 

 and from Westchester Co. Not recently collected. 



N. J. Rare and local in Hunterdon and Middlesex counties, 

 increasing but not common southward, but not in the pine- 

 barrens or east of them. 



Pa. Bucks Co. 



A rare and local plant, apparently most common on Cretaceous 



sands and gravels. 



24. Sophia Adans. 



1. S. Sophia (L.) Britton. In waste places: N. B. to Ont., N. Y. 

 111. and Neb. Naturalized from Europe. 



Occasional as a weed in most parts of our range, except in the 

 pine-barrens. 



5. pinna/a (Walt.) Howell has been reported as a waif from N. J., near Phila- 

 delphia and in Delaware Co.. Pa. 



25. Stenophragma Celak. 

 1. S. Thaliana (L.) Celak. In sandy fields and rocky places: 

 Mass. and S. Ont. to Minn., Ga. and Mo. Naturalized from 

 Europe. 

 Common throughout the area. 



26. Arabis L. 



Seeds in 1 row or in 2 incomplete rows in each cavity of the pod. 



Basal leaves pinnatifid; pods ascending. I. A. lyrata. 



Basal leaves merely dentate or lyrate. 



Seeds minute, oblong, wingless. 2 A. dentata. 



Seeds larger, oblong, winged or wing-margined. 

 Pods nearly erect, 1 mm. broad. 



Flowers white, 8 mm. broad; pods not ap- 



pressed; style I mm. long. 3. A. patens. 



