494 CLASS BASIDIOMYCETEAE 



Trametes are those forming the Tribe Daedaleae (of Bondarzew and 

 Singer, 1941). In these the pores are elongated radially or are labyrinthi- 

 form. Daedalea is distinguished by having the pores elongated or laby- 

 rinthiform. Its spore fruits are shelf-like and corky. D. confragosa (Bolt.) 

 Fr. is very common in North America and Europe. In Lenzites the pores 

 are elongated radially from the point of attachment so as to resemble 

 gills, with occasional cross connections which may disappear with age. 

 The spore fruit is more or less corky. L. hetulinus (L.) Fr. is common on 

 birch and other trees in North America and northern Eurasia. Its fruiting 

 bodies are 3 to 7 cm. broad, 3 to 10 mm. thick, velvety and zonate above. 

 But for the cross connections in the young specimens this might well be 

 placed in the Family Agaricaceae. Donk (1933) and some others follow 

 Schroeter in dividing the genus Daedalea by separating off D. confragosa 

 to form the genus Daedaleopsis. Karsten (1882) separated off from 

 Lenzites the species with rust-brown trama as the genus Gloeophyllum. 

 This would include the common Lenzites saepiaria (Wulf.) Fr., which 

 causes the decay mainly of coniferous wood. The species of this tribe are 

 very variable as to pore form. In the same species some specimens may 

 have poroid, labyrinthiform, lamelloid, or even irpiciform hymenophores. 

 The distinctions between some species of Trametes, Daedalea, and Lenzites 

 are therefore rather arbitrary. 



Undoubtedly belonging to the Polyporaceae are the species of Irpex 

 (Irpiciporus of Murrill) and probably the genus Echinodontium. Irpex 

 may be resupinate, effused-refiexed, or shelf-like. The younger parts of 

 the hymenophore are poroid but with increasing age the walls of the 

 pores grow unevenly so as to produce flattened teeth. Thus the specimen 

 comes to resemble closely some of the species of the old genus Polystictus. 

 Echinodontium has woody, shelf-like, or unguliform fruiting bodies re- 

 sembling some of the forms of the genus Fomes but with the hymenophore 

 composed of irpiciform plates which have small lateral teeth along their 

 edges. The spore fruits are brightly colored and were formerly used by 

 the Indians of Northwestern United States as a source of a red dye. It 

 causes decay of the hemlock {Tsuga) and of Fir {Abies) in Alaska and 

 northwestern United States. Both Irpex and Echinodontium were formerly 

 placed in the Hydnaceae. 



The course of evolution in this family is very uncertain. Some of the 

 Pon'a-like forms may be primitive but as very many of the normally 

 pileato or shelf-like genera may become resupinate this latter habit 

 cannot always be considered to be a proof of primitiveness. Some of the 

 Poria group may have arisen from Thck^phoraceae that were more or 

 less Corticium-like. It may be possible that from the Hydnaceae, by 

 union of the teeth into pores some Polyporaceae may have developed. 

 Probably the stratose species like Fomes have developed from annual 



