Vol. X 
JUNE, 1923 
No. 6 
AMERICAN 
OF 
OFFICIAL PUBLICATION OF THE 
BOTANICAL SOCIETY OF AMERICA 
ni.ii. mMfo 
CONTENTS 
JUI. " ^ !U23 
' X 4 / ■ 
Some effects of physiological conditions on genetic characters of wheat. 
W. F. Gericke 275 
A quantitative study of anisophylly in Acer. 
Edmund W. Sinnott and George B. Durham 278 
Is it maltose or phloridzin that is abundant in apple tissue ?. E. M, Harvey 288 
Cryptomorpha, a new section of Saxifraga.. Arthur Monrad Johnson 294 
The Bolivian species of Vernonia. Henry Allan Gleason 297 
Studies of physical and morphological changes in Bartlett pears. 
Andrew Edward Murneek 310 
The formation and degeneration of germ cells in the potato.W. J. Young 325 
The embryo of Lemna... Frederick H. Blodgett 336 
PUBLISHED 
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IN COOPERATION WITH THE BOTANICAL SOCIETY OF AMERICA 
' BY THE 
BROOKLYN BOTANIC GARDEN 
At Prince and Lemon Sts., Lancaster, Pa. 
LONDON AGENTS 
WHELDON AND WESLEY, Ltd. 
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Entered as second-class matter February 21, 1914, at the post office at Lancaster, Pa., under the act of March 3, 1879 
