

JOURNAL 



OF THE 



WASHINGTON ACADEMY 

 OF SCIENCES 



VOLUME VII, 1917 



BOARD OF EDITORS 

 X. Ernest Dorsey Adolph Knopf A. S. Hitchcock 



BUREAU OP STANDARDS GEOLOGICAL 8UBVBY BUREAU OF PLANT INDUSTRY 



PUBLISHED SEMI-MONTHLY 

 EXCEPT IN JULY, AUGUST, AND SEPTEMBER. WHEN MONTHLY 



BT THE 



WASHINGTON ACADEMY OF SCIENCES 



OFFICE OF PUBLICATION 



THE WAVERLY PRESS 



BALTIMORE, MD. 



