University of Pennsylvania, 

 Philadelphia, Pa., November 14, 1877. 



Sir : I have the honor to transmit herewith a catalogue of the plants 

 collected by your Expedition from 1871 to 1875 inclusive. 



The plan adopted has been to describe all the species obtained by the 

 Survey, unless they were described in Gray's Manual, or in vol. V, Botany, 

 of King's Reports, by Mr. Sereno Watson, or either are, or are about to 

 be, described in the Flora of California, now in preparation. 



Throughout, I have received generous aid from Prof. Asa Gray and 

 Mr. Sereno Watson. The latter gentleman contributes the entire account 

 of the Leguminosce. 



Dr. George Engelmann has elaborated for the report those orders and 

 genera with which his name has been so long and so favorably associated, 

 i. e., the Cactacece, Cuscuta, Gentianacece, Euphorbiacece, Asclepiadaccce, 

 Juncus, Agave, Yucca, Cupuliferm, and Coniferce. 



Prof. Thomas C. Porter has named and catalogued fully, with valuable 

 notes and descriptions, the plants representing the Labiatce, Borraginacem, 

 Scrophulariacece, Polemoniacece, and Polygonacece. Mr. M. A. Bebb furnishes 

 an account of the Willows, a genus to which he has given long and careful 

 study. 



Mr. William Boott contributes the paper on Carex. Dr. George 

 Vasey has carefully elaborated the Gram'mece, and his paper forms one of 

 the most valuable portions of the volume. The very full paper by Prof. 

 D. C. Eaton, of Yale College, on the Filices, is believed to be a most 

 important addition to our knowledge of the species of this order found in 

 our Southwest. Mr. Thomas P James and Mr. Austin have respectively 

 named, and, when required, described, the Musci and Hepaticce, and Prof. 



