62 THE POLYPORACEAE OF WISCONSIN. 



These tubercles and scales are perhaps the most striking characteris- 

 tics by which to distinguish the older specimens from the allied species 

 P. versicolor, P. gossypinus and P. virgineus. 



Syn. Poronidulus conchifer (Schw.) Murrill, 19, vol. 31, p. 426. 



Polystictus virgineus Sehweinitz. 



White. Pileus coriaceous, thin, tough, zonate, glabrous, radiately 

 wrinkled, tuberculose ; the margin thin, undulate ; the context floccose- 

 fibrous, white. Pores medium, round, entire; becoming thin, angular, 

 acute. 



Not common. A few specimens were collected at Star Lake by Tim- 

 berlake. The largest specimen is 8 cm. wide, 5 cm. long ; flesh 1 mm. 

 thick; pores about 2 mm. long. The specimens are more or less cespi- 

 tose, attached by a narrow somewhat deeurrent base. They are of a 

 reddish-straw color; densely concentrically sulcate; at first somewhat 

 velvety then glabrous; depressed behind. The margin is very acute, 

 more or less lobed. The pores, at first white, become tawny on drying. 

 They are small, irregular, with thin slightly dentate dissepiments. 

 The specimens grew on a much decayed piece of poplar. 



Macbride (15, p. 17) says this beautiful species is to be included un- 

 der P. concJiifer Schw., but it seems to me to be a larger, darker-colored 

 species, with larger, more irregular pores. Neither do we find any 

 scales nor tubercles on the pileus. Still the two species ar doubtless 

 closely related. 



§3. Coriacei. Pileus leathery, villous, concentrically zoned. 



Polystictus versicolor (L.) Fries. 



Pileus coriaceous, thin, rigid, applanate, depressed behind, smooth, 

 velvety, shining, marked by diversely colored zones; pores minute, 

 round, acute, lacerate, white then pallescent-yellowish. 



Next to P. pergamenus this is the most common Polystictus. It is 

 found everywhere throughout the state on all sorts of wood. The spe- 

 cies is quite variable in color as well as in form and size. It may be 

 wholly resupinate, effuso-reflexed, dimidiate-imbricated, rosetted, lat- 

 erally confluent or even substipitate. One small specimen found on a 

 stump near Elkhorn was apparently centrally stiped with the pores 

 deeurrent. 



