98 



MICRO-ORGANISMS AND FERMENTATION. 



Mucor stolonifer (Khizopus nigricans) attains a very 

 considerable size, and occurs very commonly, for instance, on 

 succulent fruits. This mould is easily recognised, since the 

 brownish-yellow mycelium sends aslant into the air thick 

 hyphse without septa. These attain a length of about 1 cm., 

 then sink their points to the surface of the substratum, and 

 send out fine, greatly ramified hyphae, resembling rootlets, 



FIG. 21. 



Mucor Circinelloides, after van Tieghem and Gay on : 1, Mycelium ; 6, main 

 branch ; c, root-like branches ; r, axillary branches ; 24, develop- 

 ment of sporangia ; 5, opened sporangia ; 6, spores ; 7, submerged 

 mycelium and budding cells. 



into the latter, whilst other hyphse rise perpendicularly and 

 develop sporangia ; other branches again form new " runners." 

 The black sporangium possesses a high, dome-shaped 

 columella, and develops a number of dark-brown round or 

 angular spores. When these become free by the absorption 

 of the sporangium wall, the columella is turned over on the 



