BULLETIN 



OF THE 



SoutHern Galilornia flcadeiny o! Sciences 



VOL. I LOS ANGELES, CAL, NOVmBCR I, 1902. joNa.9 



331 'West First Street. s-l DK. .' k i\ V 



NEW YORK 



BOTANICAL 

 GARDEN 



PREHISTORIC CALIFORNIA. 



(Continued from August Bulletin) 



BY DR. LORENZO GORDIN YATES. 



Before following the procession of animal life from the early 

 Cretaceous Age to nearly the present time, it will be interesting 

 to note the character of the flora which furnished food and shelter 

 for the great armies of herbivores and carnivores which formed 

 some of the divisions of the great faunal procession. 



As before stated, plants, having but limited means of locomo- 

 tion, are forced to accommodate themselves to the changes of cli- 

 matic conditions which many animals are enabled to escape by mi- 

 grations to more favorable localities ; and the changes of tempera- 

 ture resulting from oscillations of the earth's surface, and other 

 cosmic changes do not affect the flora of a given region so 

 quickly, nor thoroughly, as is the case with the animals. 



It is a recognized fact in natural history that, wherever life 

 finds suitable conditions, plants thrive and are reproduced ; but 

 no one plant, except a few of the lower forms, is found dispersed 

 over every part of the earth. Each of the multitude of species and 

 forms of plant life which cover the surface of the earth is by its 

 organization restricted to some certain zone or region. It grows 

 and reproduces its kind only in places where the climate and soil 

 are favorable for its particular needs. P/ants, however, like ani- 

 mals, are not all equally susceptible to changes of environment, 

 nor in the facility with which they adapt themselves to such 

 changes of their surroundings ; if they were there would be no 

 limit to their distribution, and the flora of the entire earth would 

 become uniform. 



Plants are confined within certain specified limits by the diver- 

 sity of their individual requirements, and the conditions favorable 

 for plants are governed by, and dependent upon, the universal 

 factors -of environment — air, light, soil, heat and moisture. The 

 last two of these factors are largely governed by altitude above 

 the level of the sea, and therefore subject to changes resulting 

 from the varying elevations and depressions. "It is a fact well 

 established by observation, that the same, or more or less closely 



