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 scpiaria 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 
3 All colors referred to are those in Ridgway's " Color Standards and Color Nomen- 
clature.'' 
