Or 



r^~~f 



Vol. VII No. 21 



December 19, 1917 



JOURNAL 



OF THE 



WASHINGTON ACADEMY 



OF SCIENCES 



BOARD OF EDITORS 

 N. Ernest Dorset Adolph Knopf A. S. Hitchcock 



BUREAU OF BTANDARD3 GEOLOGICAL SURVEY BUREAU OF PLANT INDUSTRY 



PUBLISHED SEMI-MONTHLY 

 EXCEPT IN JULY, AUGUST. AND SEPTEMBER. WHEN MONTHLY 



BV THE 



WASHINGTON ACADEMY OF SCIENCES 



OFFICE OF PUBLICATION 



WILLIAMS & WILKINS COMPANY 



BALTIMORE, MD. 



Entered as second-clasa matter July 14. 1911, at tho post office at Baltimore, Maryland, under the Act oi 



July IS, 1894 



