322 



APPLIED BACTERIOLOGY 



very common green mould seen on the bark of trees, old 

 walls, etc. It grows in the form of locks of cotton-wool, 

 and during sporulation forms a green fur of a peculiar 

 musty odour. The mycelium consists of horizontally 

 arranged straight or slightly undulating Jointed filaments, 

 from which the spore-bearing hyphae stand vertically up, 

 dividing at their upper ends into forks (basidia), from which 

 fine processes branch off (sterigmata) in the shape of a hair 

 pencil, and are segmented at their ends into rows of fine 



Pig. 31.^ — Pbnicillium Glaucum. 



globular spores or conidia. The mould grows well on 

 bread pap in the form of a fur which is white at first, but 

 afterwards becomes of a fine green colour. The fungus 

 grows on gelatine plates first in the form of fine threads 

 diverging from a point, and not giving rise to sharply 

 defined colonies, but radiating out over a considerable extent 

 of surface. The spore-bearing hyphse which rise above the 

 level of the gelatine are put in motion by air currents, and 

 when this occurs the shedding of the spores can be readily 

 observed. The earliest formation of spores takes place in 

 the centre of the colonies, and is indicated by a green 

 colour. The gelatine is liquefied. 



Brown Mould. — The fur formed by the ' brown ' mould is 



