True, Gordon H. 1973. The ferns and seed plants of Nevada 

 County, California. California Academy of Sciences, San Fran- 

 cisco. A listing with brief introductory essay, index to fami- 

 lies and to localities. 



Twisselmann, Ernest C. 1956. A flora of the Temblor Range. 

 Wasmann Journal of Biology, Volume 14, Univ. San Francisco, 

 San Francisco. A well-written and fascinating account of the 

 flora of this unit of the Diablo Range, its ecology, history, etc. 



. 1967. A flora of Kern County, California. Wasmann Jour- 

 nal of Biology, Volume 25, Univ. San Francisco, San Francis- 

 co. An annotated check list of the plants preceded by a 

 lengthy and excellent discussion of natural history, geography, 

 geology and soils, climate and weather, floristics, plant associ- 

 ations, numerical analysis of the flora, centers of distribution 

 and origin of the flora, range limits in Kern county, and botani- 

 cal exploration in the area. 



Watts, Tom. 1963. CaUfornia tree finder. Nature Study Guild, 

 Berkeley. A handy little pocket manual for identification by 

 the amateur of the more common native trees of CaUfornia. 



Williams, J. C, and H. C. Monroe. 1969. The natural history of 

 the San Francisco Bay area. McCutchan Pub. Corp., Berkeley. 

 Designed to foster an understanding of the natural history of 

 the area. Contains numerous illustrations and photographs of 

 the biota. 



Witham, Helen V. 1972.Ferns of San Diego County. Natural His- 

 tory Museum, San Diego. Traces the history of ferns, their 

 ancient origin, uses and beliefs in the Middle Ages, then Hsts 

 the 26 ferns of San Diego county and helps the reader to 

 identify them by drawings, photographs, and descriptions. 



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