Bui. 1417, U. S. Dept. of Agriculture 



Plate 7 



Studies of Ozonium Strand Hyph/e 



A, Cross section of an Ozonium strand from a mesquite root, showing the large central hvpha, 

 whose contents are granular, and the outer bands of hyphae. The scattered fragments on 

 the outer edge of the strand are the acicular hyphae (X 368). B, Longitudinal section of 

 an alfalfa root, showing an Ozonium strand in contact, with the root surface. Note tho 

 hyaline, acicular hyphae arising from the strand (x 75). C, Longitudinal section of an 

 alfalfa root, showing an Ozonium strand beginning to form an accumulation of hyphae pre 

 paratory to the penetration of the fungus between the cork cells (X 150) 



