4 2 PLANT LIFE. 



face of the object upon which the fungus lives ; or parts of 

 it may be superficial, and part may penetrate that object ; or 

 all of it may be hidden within the substratum.* In some of 

 the common molds (Mucorini), the cobwebby threads lying 

 upon the surface of the substratum constitute the exposed 

 part of the mycelium, while other hyphae penetrate deeper ; 



Fig. 50. — A section of part of the aerial body of Polyporus. s/>, hyphae running at an 

 angle to the section, cut across ; A", crystals of oxalate of lime. Magnified about 

 500 diam. — After Vogl. 



in others (Penicillium, etc.), the superficial hyphae become 

 so interwoven that they may be lifted off the substratum (as 

 from jellies, jams, syrups, etc. ) as a coherent layer. But in 

 most cases, especially when the fungus grows on a solid 

 medium, the hyphae become adherent to it and permeate it 

 so that they cannot be separated from it, even by the most 

 careful dissection. 



* This non-committal term may be used to designate the material upon 

 which the vegetative part of the fungus grows, whether it be a living 

 body, a dead organism, or organic matter in solid or liquid form. 



