General Features 



13 



produce a heterothallic, dioecious, or unsexual mycelium. While 



these facts have been demonstrated in one species of the asco- 



mycetes, further investigation is necessary in order to determine 



whether this is true of the operculate Discomycetes. A number 



of species of this group are known to have usually, if not always, 



four spores instead of eight. Unfortunately these forms are not 



often collected in sufficient numbers for cytological and cultural 



study. This phase of the subject also offers excellent opportunity 



for research. 



7. Spore Discharge 



Once the spores are formed, the next step, so far as the 

 fungus is concerned, is to " broadcast " them so that they 



Fig. 7. Puffing of the spores in one of the inoperculate cup-fungi, Sderotinia 



Photograph by W. R. Fisher. 



may best serve the purpose for which they were designed, that 

 of the reproduction and dissemination of the species. Probably 

 there is no group of fungi In which the apparatus for spore 

 dissemination is more highly developed than in the present one. 

 Formed in a closed sac or ascus, usually of cylindrical form, 

 they are held there for a time, apparently under high tension. 

 Finally when conditions are just right, the ascus opens in an 



