FUNGI: SAC FUNGI. 



I 9 7 



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

 character showing the general relationship of the members of the sac fungi. 



Fig. 226. Fig. 227. Fig. 228. 



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



bit of mycelium appendages. Genus uncinula. other mildew with 



T->- r> -ii / -ii dichotomous ap- 



Figs. 227 228. Penthecia (penthe- pendages . Q^^ 



cmm) of two powdery mildews, showing mirrosDhsera 



escape of asci containing the spores from r 

 the crushed fruit bodies. 



with erect conidio- 

 phores, bearing 

 chain of gonidia; 

 gonidium at left 

 germinating. 



While many of the powdery mildews have a variable number of spores in 



Fig. 229. 

 Contact o f 

 an theridium 

 and carpogo- 

 nium (carpogo- 

 nium the larger 

 cell) ; begin- 

 ning of fertili- 

 zation. 



Fig. 230. 

 Disappear- 

 ance of contact 

 walls of anthe- 

 ridium and 



Fig. 231. 



Fertilized egg surrounded 

 by the enveloping threads 

 which grow up around it. 

 Figs. 229-231. Fertilization in sphaerothcca; one of the powdery mildews. (After 



Harper.) 



in an 



carpogonium, 

 and fusion of 

 the two nuclei. 



an ascus, a large majority of the ascomycetes have just 8 spores 



