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vegetable and bulbous plants. The mycelium is septate, irregularly branch- 

 ing, and freijuently very nnicli vacuolated. It grows from the cracks in 

 the root as a white felt, later giving rise to large, hard, black sclerotia. 

 When first formed, these are white, but later they change to brown, and 

 fmally black. Mature sclerotia are white or dirty-white within, of densely 

 woven threads and with a black cellular outer coat. As in the case of 

 the Black Rot fungus, they are for the purpose of carrying the organism 

 over periods unfavurnlile to growth and for giving rise to the i>erfect 



■-''"^^"m^: 



^^. 



Fig. 5. Crown Rot of ginseng showing large, well developed sclerotia. (After Whetzel.) 



Stage. Under suitable moisture and temi)erature conditions, they send 

 out germ tubes directly, just as the Black Rot fungus. The perfect stage 

 has never been obtainetl by the writer in pure culture, although during 

 the past winter an effort was made to do so. A hirge number of sclerotia, 

 grown on various media, wore placed out of doors in sterile sand, con- 

 tained in earthen pots, and this spring one-half of them were brought into 

 the greenhouse. Some of the pots containing the sclerotia were kept very 



