Vol. VII No. 6 



March 19, 1917 



JOUENAL 



OF THE 



WASHINGTON ACADEMY 



OF SCIENCES 



BOARD OF EDITORS 

 N. r Ernest Dorsby Adolph Knopf A. S. Hitchcock 



BT/BXAU 07 STANDARDS GEOLOGICAL SURVEY . BUREAU OF PLANT INDUSTRY 



PUBLISHED SEMI-MONTHLY 

 EXCEPT IN JULY, AUGUST, AND SEPTEMBER, WHEN MONTHLY 



WASHINGTON ACADEMY OF SCIENCES 



OFFICE OF PUBLICATION 



WILLIAMS & WILKINS COMPANY 



BALTIMORE, MD. 



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



July 16, 1894 



