DISEASES IN GREENHOUSE 117 



ydospores (fig. 14^ to d) are thick walled, 

 dark brown bodies, borne on the same my- 

 celium as the endospores. This type of 

 spore is formed in great abundance on the 

 host and particularly within the affected 

 tissue. The ascospores (fig. 14/) are len- 

 ticular in shape and are borne in asci (or 

 sacs) within black perithecia (fig. 14^)- 

 This stage, however, has not been found on 

 the sweet pea or in pure culture. 



Thielavia is perhaps next in importance 

 to Fusarium root rot. The fungus is 

 often introduced with manure or more 

 comrnonly with diseased violets, since this 

 flower is profitably grown in conjunction 

 with sweet peas. 



Growers, therefore, cannot be too care- 

 ful in trying to keep out Thielavia from 

 the greenhouse. 



