ADJUSTMENTS OF FRUIT-BODIES 57 



porus or Saddle-Back Fungus, is one of the best known European 

 species of tree-destroying fungi, and it is also found in the United 

 States and Canada. Its large ochraceous fruit-bodies, checkered 

 with brown scales above, are frequently to be seen projecting as 

 brackets, either singly or in groups, from trunks and branches of 

 living trees in woods, parks, and gardens (Figs. 1 and 4-7, pp. 8, 

 28, 29, 32, and 33 ; also Plate V.). 



For the purpose of studying the development of the fruit-bodies 

 under special conditions, several logs which had been half destroyed 

 by the mycelium were procured and removed to an experimental 

 greenhouse. As this was conveniently provided with a dark-room, 

 it was possible to grow the sporophores in total darkness as well 

 as in ordinary daylight. 



When the mycelium of the fungus is about to produce fruit- 

 bodies, it grows out on to the surface of the tree trunk or branch, 

 usually at a place where the bark has been removed. It there 

 forms a more or less rounded, but somewhat irregular, stromatous 

 knob of firm consistency (Plate V., Fig. 36). When this knob 

 has reached a certain size and is less than twenty-four hours old, 

 one, or usually several, bluntly conical processes arise upon it, 

 grow straight outwards from its surface, and thus come to point 

 in different directions in space (Fig. 21, A; Plate V., Figs. 31 

 and 37). The development up to this point takes place about 

 equally well under all conditions of light. It is noticeable, however, 

 that the knobs produced in darkness are quite white and smooth, 

 whereas those arising in full daylight are somewhat brown and 

 scaly. 



When fruit-bodies develop entirely in the dark, the conical 

 processes on the stromatous knobs grow outwards into long sterile, 

 finger-like columns which are usually curved or twisted, frequently 

 flattened toward their ends, and in many cases branched. In the 

 course of three weeks, vigorous fruit-bodies may attain a length 

 of 15 cm. and come to resemble a stag's horn (Fig. 20). The 

 branches grow at their apices only ; their ends are pure white, 

 whilst the older parts become deep black, like the base of the 

 stipes in fruit-bodies developed in daylight. 



The horn-like processes just described appear to be unaffected, 



