Vol IX, 
APRIL, 1922 
No. 4 
AMERICAN 
JOURNAL OF BOTANY 
OFFICIAL PUBLICATION OF THE 
BOTANICAL SOCIETY OF AMERICA 
CONTENTS 
Hydrogen-ion concentration in its relation to wheat scab 
, . E. F. Hopkins 159 
On the physiological balance in nutrient solutions for plant cultures. 
W.F. Gericke 180 
Vegetative vigor of the host as a factor influencing susceptibility and resis- 
tance to certain rust diseases of the higher plantsi . M. A. Raines 183 
Rots of early strawberries in Florida and southern California. Neil E. 
PUBLISHED 
IN COOPERATION WITH THE BOTANICAL SOCIETY OF AMERICA 
BY THE 
BROOKLYN T30TANIC GARDEN 
At 41 North Qu' en Street, Lancaster, Pa. 
london agents 
WHELDON AND WESLEY, Ltd. 
28 Essex Street; Strand, London, W. C. 2 
Eutered m« scoood-claM matter February 21, 1914, at^he post office at Lancaster, Pennsylvania, 
under the act of March 3, 1879 
