1910.] NATURAL SCIENCES OF PHILADELPHIA. 563 



difference between C. arvense oblong i folium (Ton-.) Hollick and Britton 

 and C. arvense villosum Hollick and Britton [ = C. arvense velutinum 

 (Raf.) Britton]. The latter seems a condensed form of the drier 

 situations, intergrading perfectly with the normal form. On the 

 other hand, C. oblongifolium Torr with us seems quite distinct from 

 C. arvense L. Records include forms which have been passing for 

 both varieties. 



Delaware. — Fawkes Run; Bear Hill; Blue Hill; Mineral Hill; 

 Middletown Barrens; Williamson; Wawa. 



Chester. — Sugartown Barrens; Serpentine Ridge; Cedar Barrens; 

 West Chester; Sconnelltown [ = " Strode' s Serpentine" (Dr. Wm. 

 Darlington) type of C. villosum]; Brinton's Quarry; Unionville. 



— Nottingham Barrens. 



Lancaster. — Pleasant Grove (A. A. Heller and J. K. Small); New 

 Texas (J. J. Carter). 



*100. Arenaria stricta Michx. 



Local on dry open barren, rock exposures. 



Delaware. — "Middletown" (I. Burk)— locality likely incorrect. 



Chester. — West Chester ; Unionville. 



— Nottingham Barrens. 



101. Syndesmon thalictroides (L.) Hoffmg. 



Frequent in dry woodland. 



Dela ware. — Mineral Hill ; Williamson ; Wawa. 



102. Thalictrum revolutum D. C. 

 Occasional on dry open barren. 



Leaflets abundantly glandular-puberulent in the Nottingham speci- 

 mens, slightly so or nearly smooth beneath in the Delaware County 

 specimens. 



Delaware. — Williamson (B. Long); "Elwyn" (Dr. J. B. Brinton). 



Chester. — Nottingham Barrens. 



103. Sassafras sassafras (L.) Karst. 



Abundant on dry barrens. 



Delaware. — Fawkes Run; Blue Hill; Mineral Hill; Wawa. 



Chester. — Sugartown Barrens; Brinton's Quarry. 



fl04. Arabis lyrata L. 



Common on diy open barrens, banks and depressions. 

 Delaware. — Bear Hill; Mineral Hill; Middletown Barrens (-), Wil- 

 liamson: Lenni; Wawa. 



