CURRENT LITERATURE. 269 



species of conifers in various localities, but particularly in swampy places or 

 under conditions of extreme humidity. Heavy irrigation was found to induce 

 such lenticels as was also the pruning of the shoots. 



The literature on hypertrophied lenticels is briefly reviewed. Schenk 

 attributes the phenomenon to oxygen hunger. Later writers think, it to be 

 caused by humidity, moist air allowing the continued formation of aerenchyma 

 while dry air induces suberization and cork formation. De Vaux thinks humi- 

 dity increases lenticellular development entirely through increase of sap 

 pressure. Soraurer connects them with general pathological conditions of 

 the tree. The authors are inclined to go back to the older theory that oxygen 

 huDgeriS the main predisposing cause. They feel, however, that other factors 

 contribute to the result, and suggest that the problem can be best attacked 

 by experiments in which oxygen, carbon dioxide and water supplies in the 

 soil are independently controlled. 



L.G.K. 



Printed and Published for the Proprietor by W. L. King at the Methodist 

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