b PLANTS WEIGHTIAN^. 



herbarium ; another becomes the property of the Smithsonian Institution, which has 

 efficiently patronized this exploration. It will there form, with similar sets of the 

 collections of Fendler and Lindheimer, made in New Mexico and Texas, the 

 nucleus of an important and authentic North American herbarium, destined to be 

 enriched, I trust, by continued accessions, especially from our newly-acquired ter- 

 ritories, until it shall comprise representatives of our whole flora, and specimens 

 of all the vegetable products of our wide country. 



Another set of these plants will be found in the herbarium of John A. Lowell, 

 Esq., of Boston, who has liberally patronized Mr. Wright's scientific explorations. 

 The others, eight or nine in number, are about to be issued to the subscribers who 

 have applied for them. 



The numbers prefixed to the names are those under which the specimens are 

 distributed. Those marked with a f, in place of a number, were collected in single 

 specimens, or at least not in sufficient quantity for distribution. 



The whole will give a good idea of the vegetation, and consequently of the 

 climate, general character, and capabilities, of the region traversed. I append, 

 from time to time, notices or characters of plants gathered by other collectors in 

 adjacent regions, especially by Dr. Wislizenus in the valley of the Rio Grande and 

 in Chihuahua, and by the indefatigable Dr. Gregg * in the same district and in the 

 northern provinces of Mexico, — chiefly from materials obligingly furnished by Dr. 

 Engelmann. 



Orders or genera elaborated by Dr. Engelmann, Dr. Torrey, Mr. Bentham, or 

 others, have the name of the author preflxed. 



A proper account of the topography and physical character of the region 

 traversed by the United States troops in their march from Texas to New Mexico 

 will doubtless be officially published, before the printing of this memoir is com- 

 pleted. It is therefore unnecessary for me to attempt to compile any such account 

 from Mr. Wright's disjoined and necessarily imperfect memoranda. 



A. GRAY. 



Harvard University, Cambridge, May, 1850. 



* Tidings of the lamented death of this most assiduous collector, in California, have just been received. 



