POLYPORUS. 



443 



at first white but becoming grey, and in exhibiting an internal 

 differentiation which those of P. vaporarius do not.^ 



The hyphae in the course of their growth do not seek out 

 the pits, but grow straight through the walls and bring about 

 dissolution of the middle lamella for some distance around. At 

 the same time numerous short oblique fissures in the walls are 

 produced vertically one over the other, especially in the elements 



Fia. 275. — PolyporvLS squamosus on Acer Ifegundo. The three upper sporophores 

 are borne on a separate piece of wood, from which a fourth has been cut off. 

 (v. Tnbeuf phot.) 



of the thick-walled autumn wood. (Compare with P. sistotre- 

 nioides, Fig. 280). The phenomena accompanying destruction of 

 wood by this fungus are so characteristic that Conwentz^ could 

 distinguish it quite clearly in tree-remains enclosed in amber. 



Brefeld succeeded by artificial culture of the spores, in raising 

 a mycelium on which basidia were formed, at first directly, 

 afterwards from large sporophores. 



Polyporus squamosus (Huds.). (Britain and U.S. America.) 



1 R. Hartig, Der echte Hausschwamm, Berlin (Springer), 1885. 

 ^Conwentz, Monographie d. baltiscTien Bernsteinhaume, 1890. 



