AUTOBASIDIOMYCETES 



455 



The hyphas are hyaline, considerably septate, and often show 

 clamp connections when growing in the vessels. They grow more 

 quickly in the vessels, but are not ultimately assembled into strands 

 in these parts. The wood is eventually separated into plates or 

 cuboidal areas, and the texture of the wood becomes light and corky. 

 The separation of the wood into plates is accomplished by the 

 growth of white strands or bands of the mycelium in all three direc- 

 tions, that is, radially, tangentially, and longitudinally. The wood 

 elements, which gradually disappear under the solvent action of 



Fig. 224. Polyporvs squamosus, Upper Surface 



the fungus, are largely those which are less lignified, such as the 

 fibers between the vessels, that is, those usually produced only dur- 

 ing spring growth. In the dissolution of the cells, first the contents, 

 next the secondary cellulose layer, and finally the middle lamellae 

 disappear, so that during the process the cells do not become sepa- 

 rated in the early stages of decay. 



The mycelium unquestionably possesses a variety of enzymes. 

 According to Buller, " from an enzymotic study of wood undergoing 

 decay from the agency of Polyporus squamosus evidence was taken 

 that various enzymes are excreted by the fungus mycelium. Thus 



