THE POLYPORACEAE OF WISCONSIN. 109 



Polyporus betulinus Fries. (Plate XIII, fig. 46). 



Pilei circular, hoof or kidney-shaped, with obtuse margin, the base 

 narrowed into a short stipe, fleshy becoming corky, azonate, glabrate 

 covered with a thin separable brownish to brownish-red cuticle, size 

 variable. Pores short, small, unequal, white, separable when old. 



On trunks of Betula. 



The birch polypore is one of the commonest of polypores wherever 

 the birch grows. It is found on living as well as dead birch. Locali- 

 ties: Lake Superior region (Cheney), Star Lake, Shanagolden, Cran- 

 don, Ladysmith, Sparta and Bangor. 



Largest specimen measured 24 cm. in width, 14 cm. in length and 

 3 cm. in thickness. It was kidney-shaped and showed the short thick, 

 curved stem so peculiar to the species. 



The substance when fresh is white, soft cheesy-fleshy, but becomes 

 soft-corky on maturing and drying. The pilei are usually more or less 

 circular, umbonate and hoof -shaped. The obtuse margin is incurved, 

 and projects all around beyond the pores. The pores are at first white 

 but darken somewhat on maturing. From the hymenium project nu- 

 merous spines, thus giving it a bristly appearance. The cuticle is usu- 

 ally of a grayish color, darkening with age. Sometimes there are 

 darker colors on the top of the pileus. 



This fungus produces a white-rot in the wood of the birch. Infec- 

 tion probably occurs by the spores lodging in the cracks of the bark. 



Syn. : Piptoporus suberosus (L.) Murr. ; 19, 30, p. 425. 

 Piptoporus hetulinus (L.) Karst. ; 13, 3, p. 17. 



Polyporus hispidellus Peck. 



Pileus fleshy, tough, dimidiate, pale fawn-colored or grayish-brown, 

 clothed with short stiff hairs, flesh white ; pores small, short, subrotund, 

 white, the dissepiments thin, the edge uneven, dentate or lacerate ; stem 

 short, lateral, solid, often irregular, clothed like the pileus ; spores fusi- 

 form 12.5 microns long and 4 microns broad. 



Locality: Star Lake. The pileus has a very bitter taste. It is 

 grayish-brown on top, with a tawny hymenium. The pileus measures 

 6 cm. long and 7 cm. broad with an average thickness of about 7 mm. 

 The surface is rough with short hairs. The pores are medium, equal, 

 toothed and somewhat decurrent. The stipe is excentric, unequal, 

 bent, a little lighter than the pileus, measuring about 7 cm. long and 

 1 to 1.5 cm thick. The substance of the pileus is somewhat fleshy but 

 is thin and brittle when dry. 



