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FUNGOUS DISEASES OF PLANTS 



FIG. 43. BEAN SEEDLINGS ATTACKED BY PYTHIUM 

 (Photograph by H. H. Whetzel) 



The fungus. The mycelium, like that of most Peronosporaceae, 

 is delicate, more or less variable in diameter, and much branched. 

 The branches are, for a time, at least, smaller than the parent 

 hyphae. The protoplasm is densely granular in the growing 



