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Nebraska Agricultural Exp. Station, Research Bui. 12 
DESCRIPTION OF PLATE IX 
A, B, C, and D. Microphotographs of longitudinal sections of 
apple Vv'ood showing invading hyphae. 
In A, the hyphae are shown in the medullary ray cells as well as 
in the tracheae. 
In C, the hyphae are shown passing thru the pitted walls of two 
adjoining tracheae. 
