FUNGOUS DISEASES OF THE CABKATION. 333 



for its deTelopment and spread, as a spore will germi* 

 nate, develop a mycelium and produce a crop of epores 

 within three days. 



While particularly injurious to cuttings, it often 

 causes serious injury to the growing plants, where it is 

 most commonly found upon the lower portions of the 

 stems and the clasping bases of the leaves and leaf 

 sheaths. The diseased portions shrivel, turn brown and 



HG. 117. EFFECT OP "SPOT" ON CAENATIONS. 



at length are dotted with black, rosette-like clusters of 

 spores (Pig. 118, a) ; these stools owe their color and 

 general appearance to the development of a number of 

 long, black bristles. Fig. 118, i, shows a section through 

 one of these fruit clusters greatly magnified, the spores 

 being much shorter than the bristles. The germinating 

 spores still more magnified are shown at c. 



