

* 



* 



Fig. 10. — This ascospore, germinating within the apothecium, clearly shows the 

 typical lateral germ tube shortly after its emergence. (X 2250) 



apothecial maturation. Whether ascospore dissemination occurs 

 after needles have fallen has long been a question (28, 61). In the 

 present work, fallen needles with apothecia containing the black 

 germinating cells of the ascospores were found during the period of 

 spore dispersal. When high humidity was maintained beneath the 

 tree, as often occurred where heavy grass or thick mosses were abun- 

 dant, secondary organisms quickly invaded the entire needle, especi- 

 ally the apothecial cavities. Dried needles were greatly shriveled and 

 no ascospores could be identified among the blackened tissues of the 

 apothecia. Many infected needles lodged among the lower needles of 

 the tree as they fell, but these too dried rapidly and produced no 

 recognizable ascospores. 



The abnormally dry spring of 1957, followed by a wet, early sum- 

 mer, resulted in an excessively large number ol infected needles 

 remaining on the twigs after the ascospores wei e < ast. The i ontinued 

 high humidity also resulted in the- growth of main contaminants. 

 These weie Largely members of the genera Penicillium, Aspergillus. 



53 



