44 VEGETABLE HISTOLOGY. 



species sexual reproduction takes place, and this may be by 

 several methods, namely, conjugation, and formation of so- 

 called oospores. 



PENICILLIUM GLAUCUM (BREAD MOULD). 



This mould is familiar to everyone from its forming sage- 

 green crusts upon bread, jam, old boots, etc. It may be ob- 

 tained at any time by placing a moist piece of bread under a 

 bell-jar in a moderately warm place. When spores appear, 

 sow some in Pasteur's fluid (see under Torula). Moulds grow- 

 ing in this fluid are easier to examine than when growing on 

 bread. On examining a patch of mould on the surface of the 

 fluid, it is found to consist of a horizontal felt work of delicate 

 tubular filaments, the hypha3, forming a crust like so much 

 blotting paper, which is known as the mycelium. Hyphae pro- 

 ject from this into the air, b, and bear a green powder, the 

 spores, c, Fig. 30. These hyphae are called aerial. From the 

 mycelium other hyphae grow down into the liquid and are called 

 submerged hyphce, corresponding somewhat to the roots of 

 higher plants. 



Fig. 30. Penicillium glaucura. 



Carefully make a thin section of the mycelium by cutting 

 between two pieces of pith. Moisten a section on a slide with 

 alcohol, allow the latter to nearly evaporate, then add water 

 and cover. Examine first under low power and observe the 

 appearances described above. 



With high power, observe that each hypha has a transparent 

 wall and protoplasmic contents and is divided by transverse 

 partitions into a number of cells. Each cell has several large 

 clear spaces, the vacuoles and a number of nuclei which, how- 

 ever, are only visible by staining properly. 



