OUTLINES OF AMERICAN VEGETATION. 10? 



blasting frost and snow. Between these extremes, it is apparent, 

 vegetation assumes an intermediate character, varying as the zone ap- 

 proaches one or the other of the extremities. Both the temperate and 

 torrid zones are likewise little less distinctly divided by mountains. 

 At the base of these may be seen healthy and luxuriant vegetation, 

 while upon their summits it is characterised by that of the polar 

 regions. This, however, corresponds with the altitude of the moun- 

 tains. Some even in the torrid zone, present the climate of that of 

 the arctic regions, while others of a less elevation maintain a vigorous 

 vegetation. 



Local vegetation depends again upon the peculiar constitution of 

 plants. Some plants are so hardy and vigorous as to sustain the 

 extremes of climate, growing with little difference of vigor and pro- 

 ductiveness in both cold and and warm climates. This is most provi- 

 dentially remarkable with many of the most nutritive plants. It has 

 been said, in regard to climate upon vegetation, that the earth is com- 

 parable to two high and immense mountains with their bases united, 

 like the halves of an orange in the centre, the circumference of which 

 constitutes the equatorial region, and the summits the arctic regions. 

 It is remarkable, however, that almost every country has a vegetation 

 peculiarly its own, distinguished by the peculiarities of its natural 

 boundaries and the general character of its surface. Thus it will be 

 seen that Europe presents a very different class of vegetables from the 

 same latitudes in America. Parallels of latitude corresponding with 

 those of Africa also exhibit in America very little resemblance. Even 

 the small island of G. Britain is distinguished by a remarkable differ- 

 ence in plants on its eastern and western sides, and like differences are 

 observable on islands of corresponding latitudes. Medicinal plants and 

 drugs are particularly distinguished, in vegetable geography, by location. 



Outlines of American Vegetation. 



J? glance at the forest region of North America presents an eastern 

 and western division, with an intermediate range of underwood. 

 There are 332 genera of plants which are considered peculiar to N. 

 America. Prior to the introduction of civilization, the whole eastern 

 portion of this country, from Hudson's Bay to the Gulph of Mexico, 

 was an unbroken forest extending back to beyond the Mississippi, and 

 presenting the most extensive forest on the globe. It comprised about 

 140 kinds of trees, more than half of which rise to over 60 feet in 

 height. Among those that distinguished it were the Jim. Cyprus, the 

 hickories, the tulip tree, the locust, numerous and magnificent pines, 

 oaks, ashes, the coffee tree, magnolia, sycamore, loblolly-bay, and innu- 

 merable others of remarkable kinds. 



Vegetation is here divided into three districts ; the 1st, or northern, 



