TRAMETES. 453 



Trametes. 



Sporophores as in Polyporus, except that the substance 

 between the pores does not differ from that of the rest of the 

 sporophore.^ 



Trametes pini (Brot.) Fr.^ Eing-scale of Pine. This is a 

 dangerous forest parasite in Northern Germany ; also in Britain 

 and U.S. America. On the pine the sporophores develop from 

 brauch-scars, and assume a bracket form. The fungus has also 

 been observed on spruce in Bavaria and elsewhere, but in this 

 case, the sporophores are more frequently found as a coating 

 over the bark on the under side of a branch. Larch, silver 

 fir, and the Douglas fir (in America), have also been mentioned 

 as hosts. 



The sporophores are brown and woody, and continue to form 

 annual hymenial zones for a number of years. The hymenial 

 layer consists of pore-tubes lined with basidia, between which 

 thick-walled cystidia are formed. The spores are elliptical, and 

 on germination penetrate into wounds or broken branches not 

 protected by an outflow of resin. The older branches of pine 

 and larch have a central heart-wood from which no resin is 

 secreted, and these branches, when broken over, offer the neces- 

 sary access to the germinating spores; for this reason, infection 

 takes place most frequently in old plantations. The mycelium 

 spreads through branch and stem, particularly upwards and 

 downwards in the same year-ring. In this way longitudinal 

 stripes and peripheral zones are formed in the wood, giving rise 

 to the popular name " ring-scale." Single hyphae bore through 

 the cell- walls, and a ferment secreted by them dissolves 

 the incrusting substance, so that walls affected show the re- 

 actions for cellulose almost at once. A very characteristic 

 feature is the appearance of isolated white spots or holes, indi- 

 cating where the wood, after becoming cellulose, has been 

 dissolved out entirely. The middle lamellae are dissolved out 

 first in attacks of this fungus, the tertiary lamellae remaining 

 longest intact (Fig. 12). The dark centres of mycelium inside 



^ The distinction between the genera Polyporus and Trametes is badly defined. 

 A reinvestigation of the systematic relationships of the whole group of Polyporeae 

 would in fact be advisable. 



^ B. Hartig, Zersetzungserscheinwigen, PI. V. and VI. ; Wichtige Krankheiten, 

 PI. III. ; Lehrhtch d. Baumkraniheitcn, 1894 (English translation by Somerville). 



