Bui. 213, Bureau of Plant Industry, U. S. Dept. of Agriculture. 



Plate XXVII. 



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Photomicrograph of section through a rapidly proliferating gall on tobacco. The centers 

 of most active proliferation may be seen crowding the older parenchyma cells out of 

 place. Here and there (x, x. x) may be seen small groups of abnormal vascular bundles. 

 Margin at top. Toward the left at top is nearly unchanged parenchyma. 



