/'■ 
Vol. X 
NOVEMBER, 1923 
No. 9 
AMERICAN 
OFFICIAL PUBLICATION OF 
BOTANICAL 
sonian Inch's 
A 
fm 
CONTENTS 
Symposium—Sterility in Plants 
The physiology of incompatibilities ...........A. B. Stout 459 
Pollen- and seed-sterility in hybrids. .. Bradley Moore Davis 462 
Genetical aspects of self- and cross-sterility... .E. M. East 468 
Sterility in relation to horticulture..... . M. J. Dorsey 474 
Genera of North American Fabaceae I. Tribe Galegeae...P. A. Rydberg 485 
The cambium and its derivative tissues IV. The increase in girth of the cambium. 
I. W. JBailey 499 
Type species of the first 100 genera of Linnaeus’ Species Plantarum. 
A. S. Hitchcock 510 
PUBLISHED 
IN COOPERATION WITH THE BOTANICAL SOCIETY OF AMERICA 
BY THE 
BROOKLYN BOTANIC GARDEN 
At Prince and Lemon Sts., Lancaster, Pa. 
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WHELDON AND WESLEY, Ltd. 
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Entered as second-class matter February 2Z, 19x4, at the post office at Lancaster, Pa., under the act of March 3> 1879 
