POLYPORACEAE 



489 



underlying mycelium and the pore layer. Some species produce their 

 fruiting bodies only on the under side of branches or logs so that the 

 pores point directly downward, but this is not the case in all species. The 

 pores are mostly rather small, angular or round, and not very deep. 

 The spore fruits vary in size and color as well as in color of the spores. 

 Some species ascribed to Poria have the structure of trama and hymenium 

 characteristic of some of the species of Corticium and other closely related 

 Thelephoraceae, differing only in their poroid habit. They probably belong 

 in that family. It may be that they are intermediate forms between the 

 two groups. Aside from these forms and those that are closely related to 

 nonresupinate genera the remaining resupinate species have been divided 

 further on the basis of texture, and color of trama and spores (Murrill, 

 1907; Donk, 1933; Cooke, 1940; Bondarzew and Singer, 1941). 



The annual-fruited forms with effused-reflexed, or shelf-like or stipitate 

 structures and with membranous or leathery texture and with pileus and 

 pore trama similar and continuous were formerly included in the old 

 genus Polystictus with many hundred species. By the more recent stu- 

 dents of this group this genus has been broken up into six or eight or 

 more genera. Perhaps the commonest species of this group is Coriolus 

 versicolor (L. ex Fr.) Quel. It is very common on dead stumps, logs, etc., 

 and forms great numbers of overlapping semicircular or kidney-shaped, 

 velvety-haired pilei, which are strongly marked by zones of various colors. 

 The individual pilei are 2 to 5 cm. in diameter and may grow together 

 at the margin to form broad sheets if they are emerging from the cut top 

 of a stump. On the under side of a log they may be resupinate or effused- 

 reflexed. Hirschioporus abietinus is grayish white and hairy above and 

 concentrically furrowed, the edge of the pileus and the pore surface being 

 violet colored in fresh specimens. They are formed on branches, logs, etc., 

 being resupinate on the under side of the substratum but forming shelves 

 at the sides. Mostly on coniferous wood. The pores in age break up into 

 flattened teeth. Coltricia perennis (L. ex Fr.) Karst. grows on the ground 

 usually in coniferous forests and forms a funnel-shaped, centrally stipitate 

 spore fruit, brown and velvety above when young, glabrate with age, 

 more or less strongly concentrically marked. 



The genus Polyporus in its older limits differed mainly from Polystictus 

 in being as a rule larger and thicker and more fleshy when young, and . 

 with the trama of the pileus usually different from that of the pore layer 

 so that the latter sometimes separates from the former in age. At maturity 

 the spore fruits become cheesy or leathery or corky, rarely woody or 

 membranous. Fifteen or more genera have been segregated by some of 

 the modern students of this genus. Donk (1933) and Singer (1944) sepa- 

 rated off some of the species forming the genera Boleiopsis Fayod and 

 Scutiger Murrill, and Grifola (S. F. Gray) and placed them near the 



