Vol. VII No. 16 



October 4, 1917 



JOUENAL 



OF THE 



WASHINGTON ACADEMY 



OF SCIENCES 



BOARD OF EDITORS 

 N. Ernest Dorset Adolph Knopf A. S. Hitchcock 



BOREAO OF STANDARDS GEOLOGICAL SURVEY BTJBEAU OF PLANT INDUSTRY 



PUBLISHED SEMI-MONTHLY 

 EXCEPT IN JULY. AUGUST, AND SEPTEMBER, WHEN MONTHLY 



BY THE 



WASHINGTON ACADEMY OF SCIENCES 



OFFICE OF PUBLICATION 



WILLIAMS & WILKINS COMPANY 



BALTIMORE, MD. 



Entered as second-class matter July 14. 1911, at at Baltimore, Maryland, under the Act of 



July 16, 1S94 



