48 



THE LARCH CANKER 



TABLE SHOWING RATES OF GROWTH OP 



In agar-agar cultures numerous spermogonia were formed 

 after a few months. These spermogonia were somewhat 

 larger than those found on larch trees and, but for their 

 apices, were sunk in the substratum. They produced 

 normal spermatia which resisted all my efforts to germinate 

 them. No such spermogonia were formed in gelatine 

 cultures. 



Cultures on other media may be obtained directly from 

 spores, but on the whole it is easier to start from the my- 

 celium growing on gelatine or agar-agar. In this way 

 cultures have been grown on moistened sterilized bread 

 cubes in Erlenmeyer flasks and on pieces of branches of 

 European and Japanese larch which have been sterilized in 

 steam. On these larch stems apothecia were developed 

 completing the life-cycle from spore to spore (fig. 23) ; there 

 is no difference between such cultures obtained from the 

 parasitic or saprophytic form of the fungus. 



Mycelial cultures were also grown successfully on sterilized 



