48 THE POLYPORACEAE OF WISCONSIN. 



radiated, in every direction. Here and there they combined to form 

 a thin separable pileus upon which the irregular thin-walled pores 

 were formed. The hymenium is very uneven, due to the fact that 

 the older and central pores become somewhat elongated as in P. mol- 

 lusca. On drying the Avhole fungus shrinks and becomes a tawny- 

 yellow color. When the plant body is peeled off from the substratum 

 it feels soft and velvety. 



This species seems to be very closely related to P. mollusca and may 

 be distinguished from it by its larger pores, its looser substance and 

 its loose radiating fibres. 



Dudley (22, 41, p. 86) says that this species produces much of the 

 rot found in limiber piles. 



When dry the pileus is thin and soft, almost like white tissue paper. 

 The pores vary from 0.4 to 1 mm. in diameter ; from 0.3 mm. to 3 mm. 

 in length. 



Syn. : Polyporus radula (Pers.) ; 28, p. 407. 



Poria mollusca (Pers.) Fries. 



Fructification effused, thin, soft, white and a byssoid, radiating- 

 fibrillose border; pores developed from various centers, small, thin, 

 round, unequal, lacerate. 



This is a thin soft form more or less easily separable from the sub- 

 stratum, the soft white mycelium creeping over the substratum forms 

 centers for the development of the small very thin-walled pores, and 

 makes the so called "fibrillose-radiating" margin. The pores at 

 length become elongated and torn into teeth. 



Comparatively common. Specimens were found on the underside 

 of a sidewalk, on pine chips and running over dead leaves in the 

 woods, at Madison ; on an old, partly decayed boat at Sparta ; and one 

 specimen in a growing condition on December 28, 1899, under a poplar 

 log at Horicon. It seems abundant in fall and early winter. One 

 specimen collected by Professor Cheney near Brule river in 1897 is 

 perhaps the finest and most representative I have seen, and agrees 

 pretty well with no. 1706 North American Fungi and no. 1013 Fungi 

 Columbiani. The pores have a slightly pinkish tinge. They are 

 short, slightly angular, and shallow with very thin walls. The radi- 

 ate-fibrillose margin is especially well marked and beautiful. This 

 margin and the thin-walled pores are the distinctive features of the 

 species. 



The largest specimen collected was 30 cm. long, 10 to 12 cm. broad, 

 and the subiculum very thin. The pores vary in diameter as well as 



