[Vor. 4 
106 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
produces oidia very readily on agar. Small fragments of the 
agar containing the fungous mycelium were transferred either 
to the tops or bases of the culture blocks and so placed that 
a nocule came in contact with each block. In the first inocu- 
lations, where the water was not yet wholly taken up by the 
blocks and paper, the nocules floated, and when the jars were 
moved the oidia were scattered; thus in a few days some blocks 
were covered with a mycelium, while in others the mycelium 
was merely growing out from the nocules. Therefore, the 
methods of inoculating were changed, the oidia being scattered 
over the surface of the blocks by agitating the water intro- 
duced into the jars immediately after inoculation. 
The cultures were incubated for one year, a part of the time 
at room temperature and a part of the period in a very humid 
rotting-pit at a temperature varying from 22° C. in summer 
to 30-35° C. in winter when the steam heat could be utilized. 
The jars were watered from time to time so as to keep the 
paper beneath the culture blocks damp and the relative humid- 
ity of the air within the jars approximately 100 per cent. 
In all experiments reported in this paper the criterion on 
which fungous decay is based is the loss in weight during 
incubation. Thus, when the culture blocks were removed from 
the jars after one year, they were placed in an oven at 65° С. 
and again dried to constant weight before final weighing. A 
control on loss of weight due to sterilizing was arranged. 
Twenty-five blocks were dried, weighed, and sterilized, and 
then again dried and weighed, but, as stated above, there was 
no loss in weight unless the percentage of resin was above 
17.6 per cent. 
DESCRIPTION OF CULTURE SERIES 
Four series of cultures were prepared, and they have been 
designated, respectively, series A, B, C, and D. 
SERIES A 
In series A culture blocks of longleaf pine (Pinus palus- 
tris), shortleaf pine (P.echinata), and loblolly pine (Р.Таеда) 
were used in their natural conditions and placed in jars as 
