108 VEGETABLE DISTRICTS. 



extending south to lattitude 44* ; the 2d or middle, from thence south 

 to 35, being sub-divided east and west by the Alleganies ; and the 3d 

 or southern, from 35 to 27, after which vegetation is blended with 

 that of the tropics, especially on the Atlantic coast. 



The species begin far up in the northern division and run south to 

 the red and white pines, the Jim. Larch, etc., soon after which are 

 found the canae, the yellow and black birch, the true sugar and the red 

 maple, the red beech, the Am. elm, etc. The underwood of this divis- 

 ion consists of numerous important shrubs and small trees, while the 

 herbaceous and smaller plants comprise many species common to Sibe- 

 ria and northern parts of Europe. Every native species of the last 

 on both continents, as an invariable rule, extends to near the Arctic 

 Circle, where trees and large shrubs cease, and vegetation every where 

 within is the same. The aquatic plants have little peculiarity, the 

 more showy of the southern kinds extending far into the northern 

 division. In the desolate region of the extreme north, few vegetable 

 species are able to exist. On Melville island, lat. 74 J 30' N., the most 

 northern part to which vegetation has been traced, it consists of the 

 humble grasses, mosses and lichens. No tree appears and nothing of 

 a woody structure, save the solitary willow, 6 inches in height. The 

 red snow plant, here exists and penetrates still more northern latitudes, 

 multiplying amidst eternal snow and staining it with its crimson color. 



The middle district introduces us to the Flora of the U. S. This 

 is characterized by numerous oaks, ashes, hickories, walnuts, red birch, 

 white cedar, red juniper, pines, maples, etc. And the underwood 

 consists of innumerable varieties common in the northern, middle, and 

 eastern states. Within this district the herbaceous plants are very nu- 

 merous and many are of signal importance. Fine flowering aquatics 

 are also numerous in this division, with many important grasses of pe- 

 culiar forms. This district, as was observed, is sub-divided by the 

 Alleganies which mark a distinctive soil between the east and west, 

 and characterizes the nature of the plants. These peculiarities are 

 numerous, but are perhaps so well understood as to render a notice of 

 them unnecessary. The Alleganies themselves possess many remark- 

 able species of plants and others common to the northern division. 



The southern division, on proceeding from the middle district, pre- 

 sents an increasing variety of species and genera. While this contains 

 many plants common to the middle and even northern districts, it is 

 signalized by the tropical kinds. The evidences of an approach to a 

 tropical climate are first perceived in the cotton and rice fields. The in- 

 creased heat and humidity are strongly marked, and the vegetation is 

 more mixed, than in corresponding latitudes of other parts of the 

 earth. With the cotton and rice we find also the indigoand the sugar- 

 cane. The Cyprus of gigantic dimensions and dense masses of long 

 moss, etc., are indicative of the mixed productions. This southern 



