FUNGI: THE BLACK MOULD. 



127 



Fig. 100. 



Group of sporangia of a mucor (Rhizopus nigricans) showing rhizoids and the stolon 

 extending from an older group. 



These are small rounded or oval bodies. The wall of the 

 sporangium becomes dissolved, except a small collar around 



the stalk which remains attached be- 

 low the columella (fig. 101). By this 

 means the gonidia are freed. These 

 gonidia germinate and produce the 

 mycelium again. 



Fig. 101. 



A mucor (Rhizopus nigricans) ; at left nearly mature sporangium with columella show- 

 ing within ; in the middle is ruptured sporangium with some of the gonidia clinging to the 

 columella ; at right two ruptured sporangia with everted columella. 



