The 



Plant World 



^ 



A Magazine of General 33otany 



VOLUME 19 

 NUMBER 3 

 MARCH, 1916 



OONTXINING 



The Weight of Physical Factors in the Study of Plant Distribution 



Forrest Shreve 53 



Notes on the Ancestry of the Beech 



Edward W. Berry 68 



Books and Current Literature 78 



Notes and Comment 80 



PCBLISHED MONTHLT 



OFFICE OF PUBLICATION 



2419-21 Greenmount Avb. 



BALTIMORE. MD. 



EDITORIAL OFFICE 

 TUCSON. ARIZONA 



Rm*re<i as f*cond-cla*» matter March 9. 1912, at tue port ofEc* at Baltimore, Marjland, under the Act of July 15, 1S94 



