Vol. XX, No. 3 
August 19th, 1921 
THE 
NEW PHYTOLOGIST 
A BRITISH BOTANICAL JOURNAL 
EDITED BY 
A. G. TANS LEY, M.A., 
UNIVERSITY LECTURER IN BOTANY / 
CAMBRIDGE • 
IN CONSULTATION WITH THE STfAFF^F) f; i Q ; \ 
THE CAMBRIDGE BOTANY SCHOOL " 
1 ' : Xs % onal 
CONTENTS 
PAGE 
Permeability continued. By Walter Stiles. (With 2 figures in the text) . 93 
Osmotic Pressure, Root Pressure and Exudation. By V. H. Blackman. 
(With 3 figures in the text) . . . . . „ . . 106 
The Reversal of Geotropic Response in the Stem. I. The Effects of 
Various Percentages of Carbon Dioxide. By M. J. Lynn, M.Sc. (With 
Plate I).116 
Reviews: 
Genetics and Evolution . . . . . . . . . 124 
Some Recent Text-Books of Botany.. 132 
An Example to be avoided.. 136 
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