48 



near Alexandria, Va. (A. H. Curtiss) ; Washington, D. C. (Vasey, 

 Ward); Montgomery Co., Md. (J. D. Smith); Newcastle Co., 

 Del. (Canby, Commons); Lancaster Co., Penn. (Porter); eleven 

 miles west of Philadelphia (C. E.Smith); and abundant on the 

 hills of Staten Island, N. Y. ; also extending westward to the 

 Sierra Nevada; Sandusky, Ohio (Douglass); Ogle Co., 111. 

 (Bebb) ; Dixons, 111. (Vasey) ; Decorah, Iowa (Holway) ; 

 Amherstburgh, Ontario (Macoun) ; Belleville, Ontario (Mrs. Roy); 

 Santa Magdalena Mts., N. M. (G. R. Vasey) ; near Bozeman, 

 Montana (Scribner). 



In the eastern United States, from southern New York to 

 Maryland, this variety is apparently confined. to magnesian rocks. 

 On Staten Island it is certainly restricted to the serpentine 

 area ; with regard to the Pennsylvania localities, Mr. C. E. Smith 

 writes : " So far as I know or have ever heard, it is unknown in 

 our district (Philadelphia), except in one spot about eleven miles 

 west of the city, where the road to West Chester crosses the 

 serpentine rocks, where it is plenty;" and we have examined a 

 specimen of Dr. Darlington's collecting, marked " Serpentine 

 hill, Westchester, Pa.," while in his " Flora Cestrica," he remarks, 

 " Banks of serpentine rock, frequent ;" as to the Delaware sta- 

 tions, Mr. W. M. Canby says, "I do not know of its growing 

 elsewhere in this State, nor anywhere in this region (Newcastle 

 Co.), except on the serpentine, where it is very plentiful," and 

 Mr. A. Commons collected it " on serpentine rock, Centre- 

 ville, Del." It also appears to grow in other places on magnesian 

 limestone, though we have not been able to verify this- to any 

 extent ; specimens have been seen by us marked " Banks of 

 Susquehanna, Lancaster Co., Pa., T. C. Porter;" and Professor 

 Porter has sent us specimens from the vicinity of Easton, Penn., 

 at both of which localities magnesian limestone occurs ; and the 

 original of Dr. Torrey's C. oblongifolhun came from a region of 

 magnesian limestone near Sandusky, Ohio. Further south and 

 west than these points we have thus far been unable to follow 

 this interesting association. 



In this connection we have thought it a matter of some inter- 

 est to present the following analysis of the ash of this plant, from 

 specimens collected on Todt Hill, Staten Island, kindly made 



