Effect produced on certain Plants by Frost. 



and which are the Locust trees of the Americans, had their 

 young shoots universally destroyed, no effect whatever was 

 produced either upon the Caraganas of Dahuria or of 

 northern China, or even upon the Halimodendron, whose 

 most northern limit in the arid plains about the Irtysch in 46° 

 or 47° N. latitude, can scarcely be considered so cold as the 

 most northern range of the Locust-tree on the mountains of 

 Upper Canada. This constitutional difference between the 

 Robinias and Caraganas, may perhaps be considered a con- 

 firmation of the propriety of admitting the modern opinion 

 of their being generically distinct. 



The same cold which entirely destroyed the blossoms of 

 Azalea viscosa, and of the other American Azaleas, scarcely af- 

 fected Azalea Pontica ; and yet the geographical range of the 

 former ones reaches as high as 50° N. latitude on the moun- 

 tains of Canada, while that of the latter does not advance 

 farther than 44° north on the lower regions of the precipices 

 of the Caucasus. 



All the species of Fraxinus, even the F. excelsior of this 

 climate were killed as far as they had vegetated, with the 

 exception of F. horizontalis and F. parviflora. Of these, the 

 latter, although its native country is not well ascertained, can 

 scarcely be referred to a higher latitude than 40° or 42° north ; 

 and the former is a garden variety, the origin of which is 

 unknown, and which, indeed, is scarcely different from F. 

 rotundifolia. 



The same remarkable circumstance was observed in the 

 genus Juglans, of which the only species that was uninjured 

 was J. nigra, which is stated by Pursh to extend from New 

 England to Florida, and wlr h suffered no injury, while 



