Vol. VIII. 
MAY, 192 1 
No. 5 
AMERICAN 
JOURNAL OF BOTANY 
OFFICIAL PUBLICATION OF THE 
BOTANICAL SOCIETY OF AMERICA 
CONTENTS 
^ MAY S 't 
1.0 n-] 
Isoachlya, a new genus oi the Saprolegniaceae C. H. Kauffmain" 231 
The transmission of Rhus poison from plant to person . . James B. McNair 238 
Ths type concept in systematic botany A. S- Hitchcock 251 
The relation of certain nutritive elements to the composition of the oat plant 
James Geere Dickson 256 
PUBLISHED 
IN COOPERATION WITH THE BOTANICAL SOCIETY OF AMERICA 
BY THE 
BROOKLYN botanic garden. 
At 41 North Queen Street, Lancaster, Pa 
Entered as secortd-class matter February 21, 
1914, at the post office at Lancaster, Pennaylvania, 
under the act of March 3, 1879 
