F»ROCEEE)INQS 



OF THE 



CALIFORNIA ACADEMY OF SCIENCES 



Fourth Series 



Vol. IX, No. 2, pp. 37-67 June 16, 1919 



II 

 LIFE-ZONE INDICATORS IN CALIFORNIA 



BY 



Harvey Monroe Hall 



Associate Professor of Botany, University of CaKfornia 



AND 



Joseph Grinnell 



Director of the Museum of Vertebrate Zoology, University of California 



INTRODUCTION 



An increasing number of naturalists, both botanists and 

 zoologists, are finding in the life-zone system a useful means 

 of handling the facts of distribution. The satisfactory 

 diagnosis of life-zones in the field has been dependent hitherto 

 upon an extensive familiarity with the occurrence of plants 

 and animals over large areas, and this has been possible only 

 to a few persons with abundant opportunity for field work. 

 It is the experience of the present writers that certain critical 

 species can be selected as "life-zone indicators", through the 

 recognition of which the zonal position of any one locality 



June 16 , 1919 



