Dr. Hooker on American Botany. 117 



Lyon, an Englishman, and an eminent collector, were found 

 to be enriched wilh a number of new and valuable plants; 

 and Mr. Pursh affirms, that through Mr. Lyon's means, more 

 rare and novel plants have been introduced from thence to 

 Europe than through any other channel whatever. The her- 

 barium, as well as the living collection of Lyon, was of great 

 use to Mr. Pursh ; and the plants described by him, from spe- 

 cimens seen only in that herbarium, are numerous. 



The interesting expedition of Messrs. Lewis and Clarke 

 across the vast continent of America to the Pacific Ocean, by 

 the way of the Missouri and Great Columbia rivers, was pro- 

 ductive of a small collection, of about 150 species of plants, 

 (but of which not a dozen were previously known to the na- 

 tives of America,) which Mr. Pursh had the opportunity of 

 describing. These were gathered during the rapid return 

 of the expedition from the Pacific Ocean towards the United 

 States. A far more extensive herbarium had been formed 

 by the same expedition on the ascent towards the Rocky 

 Mountains, and among the chains of the Northern Andes ; 

 but this was lost, in consequence of the inability to carry it 

 beyond a certain point. 



Another set of specimens to which Mr. Pursh had free ac- 

 cess, was that belonging to Mr. Ensley, a German naturalist, 

 who had been sent out to America by Prince Lichtenstein. 

 It was particularly rich in the vegetable productions of Lower 

 Louisiana and Georgia. 



Thus, by Mr. Purslfs personal exertions and industry, 

 and by the aid of other botanists, he found himself about the 

 year 1807, in possession of materials for a Flora of North 

 America, amounting to nearly double the number of species 

 enumerated by Michaux. He began seriously to think of 

 publishing them, and applied to some bookseller in Philadel- 

 phia for that purpose ; but his intention was deferred in con- 

 sequence of his being called upon to take the management of 

 the public Botanic Garden at New York, originally establish- 

 ed by Dr. David Hosack, and his private property. Here, 

 again, keeping his favourite object respecting the publication 

 of a Flora in view, he had the opportunity of adding farther 

 to his knowledge of the plants of the United States, and of 

 obtaining still greater assistance, particularly from M. lo 



