FUNGI OF IMPORTANCE IN THE DECAY OF TIMBERS. 19 



where damp chamber conditions prevail, and the sow bugs are pres- 

 ent in the same environment, particularly where the light is weak. 

 Such conditions are common in and around many structures. 



Springtails also are of common occurrence in the fungus pit, and 

 are found commonly on the moist decayed wood. It is possible that 

 other insects which inhabit buildings, such as cockroaches and spi- 

 ders, may take some part in disseminating basidiospores. In mills 

 there is the possibility that insects may assist in the dissemination 

 of these fungi as much as they assist in ordinary cases out of doors. 

 Insects of several unidentified species feed upon the fruit bodies of 

 both Lentinus lepideus and Trametes serialis to such an extent that 

 sound specimens can be obtained only within a short time after for- 

 mation. Insects coming in contact with fruiting surfaces can not 

 fail to carry away spores, because of the nature of their appendages 

 and the stickiness of the spores, as has been demonstrated. 



MYCELIUM. 



PREPARATION OF CULTURES. 



The cultures of the five fungi used in the physiological studies 

 were derived from single spores of the collections already noted. 

 The method of obtaining the single-spore cultures was essentially 

 that of Keitt {27). The basidiospores were allowed to swell, and 

 before the germ tubes developed several were picked out and trans- 

 ferred to tubes of malt agar. 



MACROSCOPIC APPEARANCE OF CULTURES GROWN AT ROOM TEMPERATURE. 



In cultures of Lenzites sepiaria on malt agar no aerial growth 

 is seen until a day or two after the submerged mycelium has ap- 

 peared, and in some cases, especially in the dark, very little aerial 

 mycelium is in evidence at all. The aerial growth (secondary my- 

 celium) is very scant, at first white, and breaks up almost entirely 

 into oidia, which give the surface of the culture a more or less 

 damp-powdery appearance. In three weeks to a month this super- 

 ficial growth may become avellaneous to wood brown. 3 The writer 

 has seldom seen anything but this secondary mycelium which breaks 

 up into oidia, but occasionally a tertiary growth will appear over 

 the oidia- forming mycelium, forming a more matted or patchy 

 growth. At optimum temperature (30° to 34° C.) a 10-centimeter 

 Petri dish is covered in about eight days. On wood the superficial 

 growth is equally scant. The surfaces of the blocks become spar- 

 ingly flecked with a white, coarse powdery growth, which is found 



'All color-H r'f«rrc(J to an.- those In Ridgway's "Color Standards and Color Nomen 

 clature.'" 



