502 PKACTICAL BOTANY 



of maturity consists of the following successive 

 layers 



a. The primary membrane of the gametes, which 

 remains thin, but persistent as an external covering. 



I. The epispore, which is a dark-coloured firm or 

 brittle layer with hemispherical wart-like outgrowths 

 from the surface. 



c. The endospore, which is thicker and more 

 transparent. 



Note how numerous though irregular are the septa 

 in mycelium which has produced zygospores. 



It is not an uncommon thing in Sporodinia to find 

 that the two gametes may not come in contact, and no 

 zygote be found ; but still each gamete may develop 

 into a body resembling a zygospore in the character of 

 the wall, the contents, and in the mode of germination. 

 These bodies are called azygospores. 



Attempts should be made to germinate the zygospores. This 

 may be done by keeping them under observation in fresh water 

 for some weeks during the autumn, changing the water fre- 

 quently : the brown epispore ruptures, the endospore protrudes, 

 and forms two to four germinal filaments. If such germinating 

 spores be now cultivated on a moist substratum, the filaments 

 may form gonidiophores of the Sporodinia type. 



