290 MTJCOR. 



which pierces the oogonium-wall, the male nucleus passing 

 through the ruptured tip of this "fertilising tube" into 

 the oosphere. The oospore secretes a thick wall, lying 

 freely inside the oogonium, and its contents are densely 

 granular and oily. 



MUCOR. 



418. Material for Study. Mucor is the common 

 " black mould " which appears in about a week on damp 

 bread kept under a bell-glass. Various other Fungi may 

 appear in addition, but Mucor is easily recognised by the 

 outgrowth from the fluffy white mycelium, after a few 

 days, of the erect gonidiophores, each bearing at its tip 

 a small black head the gonidangium. 



To prevent the bread from becoming too wet and mushy, 

 set a tumbler inverted in a plate of water, place on the 

 tumbler a piece of bread that has been allowed to get 

 rather stale by exposure to the air for a day or two, and 

 cover the whole with a bell-glass. 



419. Mycelium and Gonidiophores. Pick up with 

 needles, or with a knife-point, some of the bread on which 

 Mucor is growing, tease it out gently in water on a slide, 

 and note the following : 



(a) The branched mycelium, consisting of thick pri- 

 mary filaments (hyphae), which give off thinner branches, 

 these again branching repeatedly and ramifying through 

 the bread and becoming finer as branching proceeds. 



(6) The absence of transverse walls, the hyphae being 

 unseptate (coenocytic) . Sometimes, however, septa are 

 found in the hyphae, especially in old cultures which have 

 produced gonidangia. 



(c) The thick straight unbranched gonidiophores, each 

 ending in a spherical gonidangium. Many of the older 

 gonidangia will have burst open. 



(d) To make out the structure of the hyphae of the 



