10 THE BROAD-SCLEROPHYLL VEGETATION OF CALIFORNIA. 



is a factor in them. These subjects are of great scientific interest 

 in themselves. They are also fundamental to a proper understanding 

 of the economic relations of the species. The main emphasis in 

 this paper is laid upon these three subjects, though new material 

 is offered along all the other lines mentioned, except taxonomy. 

 The plan of treatment is to pass from the general to the specific. 

 The first two chapters deal with phytogeographic relations, the 

 next three with local units, their development and relation to habitat, 

 and the last treats of the ecological character of the individual plant. 

 An annotated list, with much detail that may not interest the average 

 reader, has been added as an appendix. 



The field work was of the two usual sorts: intensive instrumental 

 and quadrat study, and extensive exploration. The former was 

 carried on mainly in the vicinity of Palo Alto from November 

 1912 to September 1915, and in the summers of 1916, 1917, and 

 1919. The exploration covered the whole extent of the Coast Ranges 

 from San Diego to Eureka, and a number of representative localities 

 in the Sierras. 



ACKNOWLEDGMENTS. 



I wish to express first my deep appreciation of the very great 

 kindness of every one of the faculty of botany at Leland Stanford 

 Junior University, who put all the facilities of the department at 

 my disposal and who frequently gave me their personal assistance 

 in many ways. Mr. S. B. Parish of San Bernardino, Dr. L. R. 

 Abrams of Stanford University, and Dr. H. M. Hall and Dr. W. L. 

 Jepson of the University of California read the manuscript of the 

 floristic portion and made important corrections and suggestions. 

 Dr. Charles F. Shaw, of the University of California, furnished 

 the mechanical analyses of the soils from Jasper Ridge, and Dr. 

 Charles B. Lipman supplied the humus determinations of the same 

 samples. Dr. D. T. MacDougal, of the Carnegie Institution of 

 Washington, offered valuable advice and encouragement, and 

 the Carnegie Institution rendered financial assistance which was 

 applied to the purchase of apparatus. Mr. Frank Shaw, of Redwood 

 City, gave faithful and efficient assistance in the field work at Palo 

 Alto. The photo-micrographic negatives for plate 20 were the 

 work of Dr. C. O. Rosendahl, of the University of Minnesota; 

 Miss Vinnie A. Pease executed the camera drawings of the leaf- 

 sections (figs. 22-43), and Miss Elsa Horn made the multitudinous 

 measurements and calculations involved in the studies of leaf char- 

 acter in relation to habitat and of transpiration. Miss Horn also 

 rendered efficient service in the carrying out of experimental soil 

 studies and in making certain drawings. To all these persons I 

 wish to express my sincere gratitude. 



