FUNGI: SAC FUXGl. 



197 



415. Number of spores in an ascus. — The ascus is the most important 

 character showing the general relationship of the member^ of the sac fungi. 



Fig. 226. 

 Willow mildew ; 

 bit of m y c e 1 i u tn 

 ■with erect conidio- 

 phores, bearing 

 chain of gonidia; 

 gonidium at left 

 germinating. 



Fig. 227. 



Fruit of willow mildew, showing hooked 



appendages. Genus uncinula. 



Figs. 327 22S. — Perithecia fperithe- 

 cium") of two powdei^y mildews, showing 

 escape of asci containing the spores from 

 the crushed fruit bodies. 





Fig. 2:^3. 

 Fruit bod\' of an- 

 other mildew with 

 dichotomous ap- 

 pendages. Genu? 

 micrijsphiera. 



"While many of the powden- mildews have a variable number of spores in 



Fig. 2 2g. Fig. 230. 



Contact of Disappear- 



antheridium ance of contact 



and carpogo- walk of anthe- 



nium ( carpogo- ridium and 



nium the larger carpogonium, 



cell) : begin- and fusion of 



ning of fertili- the two nuclei. 



zation. -^ 



Figs. 229-231. — Fertilization in spha-rotheca; one of the powdery mildews. ( Att^ 



Harpur.) 



Fertilized egg surrounded 

 by the enveloping threads 

 which grow up around it. 



an ascus, a large majority 



uf the ascomyceles have just S spores in an 



