THE GENUS MUCOR 



387 



Does the latter become acid or alkaline ? 

 Is casein precipitated or dissolved ? 

 Note the odour of the milk. 



Q 



5. The genus Mucor embraces another group of small 

 moulds, one of the commonest representatives being 

 Mucor Mucedo, L. 



(i) Mucor Mucedo, L., leads a saprophytic life, and 

 is very commonly found as a white fluffy mould upon 

 damp bread, jam, decaying fruit, and other organic 

 materials, especially those containing sugars and starch. 



It is frequently seen on damp horse-manure, and 

 also occurs upon butter and cheese, in which it sets up 

 decomposition of the fats and proteins. 



The mycelium differs from that of the previously 

 mentioned fungi in being unsep- 

 tate, or without divisions across 

 its hyphae. The fertile hyphae 

 are erect, unbranched, and bear 

 on their ends round structures, 

 100 to 200 /A in diameter, termed 

 sporangia, inside which are pro- 

 duced a large number of smooth, 

 transparent, oval spores, usually 

 about 12 to 18 /-o long and 6 

 to 8 /A broad (Fig. 54). 



The apex of the sporangial 

 hyphae or sporangiophore extends 

 some way into the interior of 

 the sporangium as a cylindrical or ovoid bladder-like 

 projection termed the columella. 



Most species of Mucor give rise to a sexually-produced 

 kind of spore a thick-walled, black-warted zygospore 



a o c 



FIG. 54. Sporangia of Mucor 



Mucedo, L. 



a Magnified 5 diameters. 

 b Magnified 400 ,, 

 c Spores ( X 500). 



