r ol. LIV 



THE 





July 1912 



Editor: JOHN M. COULTER 



CONTENT* 



The Development of the Vascular Structure of Dianthera 



Americana 



W. Ralph Jones 



The Toxic Action of Organic Compounds as Modified by 



Fertilizer Salts 



Oswald Schreiner and J. J. Skinner 



The Effect of External Conditions upon the After-Ripening 



of the Seeds of Crataegus Mollis 



Wilmer E. Davis and R. Catlin Rose 



The Structure of the Stomata of Certain Cretaceous Conifers 



W. P. Thompson 



Briefer Articles 



Eduard Strasburger 



Charles J. Chamberlain 



Current Literature 



The University of Chicago Press 



CHICAGO, ILLINOIS 



Agents 





THE CAMBRIDGE UNIVERSITY PRESS, London and Edinburgh 



WILLIAM WESLEY & SON, London 



TH. STAUFFER* Leipzig 



THE MARUZEN -KABUSH1KI --KAISHA, Tokyo, Osaka, Kyoto 



m 



