THE GENUS PENICILLIUM 379 



fine cottony filaments termed hyphce. Each hypha is a 

 transparent tube - like structure filled with colourless 

 protoplasm, in which are vacuoles or spaces filled with 

 water containing various substances in solution. In the 

 younger parts of the hyphae the protoplasm, in which 

 small oil-globules are frequently abundant, fills the whole- 

 tube, but in the older portions it is found only as a thin 

 lining on the inside of the hyphal filament. 



Growth goes on at the top of each hypha. 



Placed across the hyphae of Penicillium at irregular 

 intervals are thin transverse partitions or septa, and these 

 are present in, all except the lowest orders of fungi. 



In most of the common moulds the body of the plant 

 may be divided into two parts, namely : 



(1) The vegetative portion, named the mycelium or 

 spawn, consisting of a tangled mass of hyphae, which is 

 generally embedded in the bread, cheese, or other 

 material from which the fungus obtains its food. 



(2) A more or less specialized portion, which bears the 

 reproductive organs. 



Reproduction among fungi is carried on by means of 

 single-celled structures termed spores. 



In Blue Mould these are borne in chains on sterigmata, 

 which are arranged in a whorled pencil-like fashion at 

 the ends of erect fertile hyphae, as depicted in Fig. 5 I . 

 Spores produced at the end of hyphae and not enclosed 

 in spore cases are frequently spoken of as conidia. 



Some, if not all, of the species of Penicillium, have 

 the power of forming fruiting bodies, inside which are 

 spores of another type (ascospores) : for further details 

 upon these structures the student is referred to special 

 text-books on fungi. 



A number of apparently different species or varieties 



