INTRODUCTION. 



Act of the Legislature, passed in 1860, authorizing a geological 

 ** Survey of the State of California, required, among other things, a " full 

 and scientific description of its botanical productions." In accordance with 

 this requisition, the material necessary for such a description was assiduously 

 collected by the Geological Corps, whenever and wherever it was possible 

 to carry on this work in addition to the other more pressing duties of the 

 Survey proper. During the years from 1860 to 1864, the botanical collect- 

 ing was entirely under the charge of, and mostly performed by, Professor 

 W. H. Brewer. It was under his supervision that the bulk of the material 

 was accumulated, the elaboration of which has formed the basis of the 

 present volume. Professor Brewer having left California in 1864, no farther 

 continuous and systematic collecting was attempted by the Survey. Mr. 

 H. N. Bolander was, however, engaged for a few months in 1866 and 1867 

 in making a more thorough botanical exploration of portions of the Sierra 

 Nevada than had before been possible ; and he also made a trip through the 

 Coast Ranges, north of the Bay of San Francisco, in which he was assisted 

 from the funds of the Survey, then, as always, entirely inadequate to a 

 vigorous prosecution of the work in all its branches. Dr. J. G. Cooper, 

 Zoological Assistant of the Survey, during a winter spent at Fort Mohave, 

 and on the way thither and back, made important additions to the botanical 

 collections. On the return of Professor Brewer to the East, in 1864, arrange- 

 ments were commenced for working up the collections, with a view to the 

 publication of a Flora of California, or a systematic description of the plants 

 growing spontaneously over that wide area of between 150,000 and 160,000 

 square miles.* The total number of species thus included was estimated at 



* In point of fact, in the present volume the botany of the whole eastern slope of the Sierra 

 Nevada, and of the ranges adjacent to it on the east, from Arizona to Northern Nevada, and 

 of Southern Oregon, has been fully worked up, and a considerable number of species included 

 which have not yet been found within the borders of the State of California, although many 

 of them, in all probability, will be. 



