THE POLYPORACEAE OF WISCONSIN. 63 



The pileus is always more or less silky with several darker, shining, 

 concentric zones, which, however, are sometimes absent in certain 

 darker varieties. They are quite thin — 1 to 3 mm. — but sometimes as 

 much as 7 or 8 mm. thick at the base. The margin is always very 

 acute, wavy, rounded or lobed; sometimes lighter in color — as invar. 

 albo-marginatus Pk., or concolorous, or darker; either incurved or 

 explanate. The pores are either white or yellowish; very small and 

 shallow, but become lengthened and torn with age. 



One resupinate specimen which had vesicular pores, thus being a 

 Myriadoporus, was found on a log near Lake Mendota. The reason 

 for this distorted growth seemed to be that the log had been turned 

 over so that the hymenium faced upwards, and thus in the endeavor 

 to readjust itself to its changed conditions, it formed the cellular pores. 



Var. albo-marginatus Fries. 



Specimens of this variety are sometimes found. It is described 

 thus: "Pileus as in type but the margin rather broadly covered by 

 white hai?^s often definitely separated from the darker part by a glab- 

 rous zone ; pores white, often lacerated. ' ' 



Closely related to P. zonatus, P. planus, P. liirsutus, and P. veluti- 

 nus. It is thinner and smaller than any of these except P. planus. None 

 of them, however, have the characteristic shining zones. Von 

 Schrenk discusses the destructive work of this fungus on timber and 

 describes the heart rot of living catalpa due to it which ultimately 

 brings about the death of the tree and the destruction of the trunk. 

 The white mycelial strands are said to enter the tree through the 

 roots, causing them to rot off, and in a few years the tree dies. It 

 is recommended that wounds in the roots be covered with pitch or 

 coal tar and also that the base of the trunk should be protected in this 

 way. 



Syn. : Boletus atro-rufus et variegatus (Schaeff.) ; 27, Taf. 268 

 and 263. 



Coriolus versicolor (L.) Quel.; 19, vol. 32, p. 642. 



Polystictus zonatus (Nees) Fries. 



Pileus coriaceous to suberose, convex, tuberculose and gibbous be- 

 hind, subzonate villous ; margin becoming white ; pores minute, round 

 or angulate, obtuse, whitish. 



Probably not very common. A few specimens were found near 

 Horicon in December 1899, and some at Elkhorn and Bangor and a few 



