82 College of Forestry 
made from old oidia- forming mycelium, repeatedly resulted 
in the formation of a basidospori ic hymenium similar to the 
one just described, thus completing the life history of this 
fungus. 
REACTIONS OF THE SPOROPHORES TO EXTERNAL STIMULI. 
Relation to Water.— Buller (1909) has ably emphasized 
the xerophytism of the hymenomycetous stick or log flora. 
While the same author has demonstrated that the sporophores 
of many of the wood-inhabiting fungi are able to withstand 
dessication unharmed — some upwards of four years — the 
resistance of the mycelium to dry conditions still requires 
experimental investigation. It may be that the xerophytism 
of a fungus is only partial — that dessication is fatal to the 
mycelium but harmless to the sporophores. However, the 
rapidity with which sporophores, on the event of rain, de- 
velop upon sticks which have been dessicated for weeks in 
the summer, points to the conclusion that the mycelium in 
the wood frequently must retain its vitality in a state of 
dessication for long periods. Bayliss (1908) was able to 
develop new sporophores on a stick bearing a number of 
sporophores of Polyporus (Polystictus) versicolor (L.) Fr. 
that had been kept four years as a museum specimen, by 
keeping it in a moist chamber for a month. The old sporo- 
phores, however, upon being revived, did not shed any spores 
but became discolored and appeared to have lost their vitality. 
This observation seems to prove conclusively that the myce- 
lium in the wood must have retained its vitality for four 
years in the dessicated condition. 
An experiment similar to the above one was tried with 
Polyporus pargamenus. A bolt of a trunk of a white oak 
(Quercus alba Linn.) was cut by the writer in November, 
1914, and stored on a shelf in the cellar. In Novem- 
ber, 1916, a section was sawn off this bolt, moistened, and 
kept in a moist chamber for over two months. At no time, 
however, could active mycelium be observed — at least none 
other than that of various moulds. While the writer had no 
