320 



APPLIED BACTERIOLOGY 



differ from the two former varieties by forming branched 

 hyphse, known as basidia, on the terminals of which are 

 seen the sterigmata, from which the conidia, or spores, are 

 separated in the form of chains. 



4. Oidiaceae. — The hyphse of the Oidiacese form no 

 special spore - bearing organs, but the hyphse become 

 articulated at their extremities, and so divide off the spores 



Pig. 29. — Mucob Mucedo. 



in the form of segments. The most important members of 

 these groups are the under-mentioned : 



Mucor mucedo. — This is the commonest mould, and is 

 frequently seen growing upon food- stuffs, particularly stale 

 moist bread and upon animal excreta. It possesses a 

 branching mycelium with hyphse bearing the swollen 

 sporangia, or spore-bearers. This mould grows well on an 

 acid medium, forming a white fur, and bears black fructifi- 

 cation heads. It is not pathogenic. 



Mucor rhizopodiformis forms a similar growth to the above. 

 A culture on bread gives rise to an aromatic odour. 



Mucor corymbifer forms a dense white fur on bread, re- 

 sembling cotton- wool. 



Mucor ramosus grows upon bread and potato as a white 

 fur which soon changes to grayish-brown. 



