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., Ill. 
(Bebb); Dixons, Ill. (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. oblongifolium 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 
