38 



where the spores of this fungus find a most suitable place for entrance 

 into the trunk. The spore germinates and the mycelium grows down 

 through the dead heartwood of the branch. From there it spreads 

 through the heartwood of the trunk, growing both up and down. The 

 growth in these directions takes place more rapidly than the lateral 

 growth. When the sapwood is reached, the progress is a slow one, 

 owing to the resinous contents. At about this time the sporophore 

 begins to form. The wood of the callus and the liying sapwood of the 

 knob become so thoroughly impregnated with turpentine that the 

 mycelium does not grow in them, but grows out through the dead 

 wood of the branch. At the first point where the hyph^e can reach 

 the air without haying to go through the collar of sapwood they 

 emerge. Where the dead branch has broken off close to the callus the 

 hy^ph^ grow out from the stub and form a cushion on it. More 

 frequently, howeyer, the red-brown cushion is formed at the point where 

 the liying callus touches the dead wood (PI. XII, fig. 5). The cushion 

 is at first yer}" small and looks as if coyered with yelyet. The hyphae 

 rapidl}^ grow radially and form a sheet which adjusts itself to the 

 shape of the callus and branch. At the edges this sheet projects from 

 the bark and forms an irregular shelf, the top of which after a time 

 becomes zonate and brown-hairy, as in the more strictl}^ bracket-like 

 forms. On many old Spruces there are deep clefts between the yari- 

 ous bark scales, and in them sheets of the sporophores form whose folds 

 fill the creyices completely, forming pores on the outer surface of the 

 newer bark and the inner surface of the old scale. Growth takes place 

 rapidty during the latter part of summer and early fall so far as could 

 be noted. The hyph^e at the edge extend the area of the sheet, while 

 those forming the walls of the pores grow yertically downward. 

 Within the pores many hyphfe grow into the holes, so that after a 

 3^ear or two these are complete!}" plugged at the base. There are at 

 present no means of judging how old one of the sporophores described 

 may grow to be. The oldest one found was about four-fifths of an 

 inch (2''°') in thickness. 



Trametes pini forma ctbietis was found but rarely on the Fir. Its 

 sporophores assume on this tree a different habit from those on the 

 Spruces. On yertical surfaces a distinct sessile pileus is formed, 

 resembling a bracket, rather than a hoof, as do those on the Spruce. 

 The mycelium, after haying grown throughout the heartwood, grows 

 into the sapwood, where it flourishes much more yigoroush' than in 

 the Spruce because of the absence of ]-esin. From the sapwood the 

 hyph{B enter the bark and break through it all oyer the trunk. At 

 the points where they emerge they form small cushions, light red-brown 

 in color, which are at first the size of a pin head, but rapidh^ increase 

 in size (PI. XII, fig. 1). When barely /g of an inch (2 '"'") in width, a 

 differentiation into an upper and lower surface takes place. A band of 



