VOLUME 2 2 

 NUMBER 4 



APRIL, 1919 



CONTAINING 



Early Spring at the Grand Cafion Near El Tovar. Alice Eastwood 95 



A Thermo-Electrical Method for the Determination of Leaf Temperature. 

 Edith Bellamy Shreve 100 



The Flora of the Pine Belt of the San Antonio Mountains of Southern 

 California. I. M. Johnston 105 



Books and Current Literature 123 



Notes and Comment 127 



PUBLISHED MONTHLY 



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baltimore, md. 



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TUCSON, ARIZONA 



Entered as second-class matter March 9, 1912, at the post office at Baltimore, Maryland, under the act of July 16, 1894 



