FUNGI: THE WILLOW MILDEW. 



137 



filaments, the appendages. Each one of these appendages is 

 coiled at the end into the form of a little hook. Because of 

 these hooked appendages this genus is called uncinula. This 

 rounded body is the perithecium. 



229. Asoi and ascospores. — While we are looking at a few of 

 these through the microscope with the low power, we should 

 press on the cover glass with a needle until we see a few of the 



Fig. 116. 



Fig. 117. 



Willow mildew ; bit 

 of mycelium with 

 erect conidiophores, 

 bearing chain of 

 gonidia ; ' gonidium at 

 left germinating. 



Fruit of willow mildew, showing hooked ap- Fruit body of an- 



pendages. Genus uncinula. other mildew with 



Figures 116, 117— Perithecia (perithecium) dichotomousappen- 



of two powdery mildews, showing escape of dages. Lrenus 



asci containing the spores from the crushed microspna^ra. 

 fruit bodies. 



perithecia rupture. If this is done carefully we see several 

 small ovate sacs issue, each containing a number of spores, as 

 shown in fig. 116. Such a sac is an ascus, and the spores are 

 ascospores. 



