uriance in the vegetation of North and South America which 

 is unequalled by any other portion of the globe. And as one 

 extremity of the United States is influenced by the severity 

 of polar cold and the other powerfully affected by equa- 

 torial heat, while the far greater part, as already remarked* 

 is found under temperate latitudes, we should expect what 

 we know to be the fact, that the variety of our plants would 

 be peculiarly great. But that we may the more clearly dis- 

 cover the advantages enjoyed in the United States for the 

 study and improvement of Botany, allotf me to present you 

 with a sketch, a little more distinct, of the face of the coun- 

 try, and of its soil and climate ; with a cursory notice of 

 some of the plants already known. 



That vast chain of mountains which extends in a north 

 and south direction, across the United States, is the most 

 striking feature of the country. This great ridge is inter- 

 sected by many others, which, though comparatively small, 

 are, when separately taken, by no means inconsiderable. 

 These mountains are generally of the primitive formation. 



The rivers which descend from these mountains, are an- 

 other striking characteristic. The St. Lawrence, the Hud- 

 son, the Susquehanna, Ohio, and Missisippi ; whether we 

 consider the length of their course, or the quantity of then- 

 water, may vie with any in the old world. 



Our lakes are no less conspicuous and peculiar than our 

 rivers and mountains. Huron and Superior, Ontario and 

 Erie, are without rivals, and almost without resemblance, 

 in any other part of the globe. 



Now it is lo be remembered that the banks of rivers, the 

 bases of mountains, and the margin of lakes, are always 

 sought after by the Botanist, as particularly favorable to his 

 researches. 



The soil at the base of our mountains towards the Atlan- 

 tic, is generally composed of a rich mould, from two to four 

 feet in depth. Nearer the ocean a clay soil, mixed with 

 loom seems to predominate.* 



* Rush's Medical Enquiries and Observations also Proud'6 Histo- 

 ry of Pennsylvania. 



