S4 College of Forestry 
over both the upper and hymenial surfaces of the sporophores, 
also enlarged extensively by outgrowths from the margins. 
(Plate XTX. ) The rev ival of the sporophores of Polyporus 
pargamenus is to be attributed to a direct outgrowth from 
the old tissues, beginning at the base of the individual sporo- 
phore and spre: ading gradually to their margins. Later in 
the fall of 1916 the tree bearing these sporophores was cut 
down and burned incident to the improvement of the grounds 
on which it stood, so that the possibility of future observa- 
tions was necessarily precluded. From the observations 
recorded above, however, it is evident that sporophores of 
Polyporus pargamenus which have remained in a dessicated 
state for nearly a year (possibly more), under certain condi- 
tions, may revive and produce a new growth in the form of 
surface additions, formation of a new hymenial layer and 
spores, or additions to the margin. Peck (1880) has like- 
wise observed that this plant sometimes revives to a certain 
extent the second season by putting on a new hymenium and 
a new growth from the margin of the pileus. In addition 
the writer has also observed the revival and growth of old 
sporophores taking place frequently when blocks from logs 
bearing sporophores are kept in a moist chamber for a few 
weeks. 
Buller (1909, p. 111), in a list of ILymenomycetes with 
sporophores which can become dessicated without losing their 
vitality, states that the sporophores of Polyporus pargamenus 
recovered after dessication for one year, the recovery being 
judged by their ability to shed viable spores upon being 
feed The xerophytism of the plant is further exemplified 
by the ability of the spores to germinate and produce infec- 
tious mycelium, after having been shed and kept in a state 
of total dessication for ten mathe as described earlier. 
Gravity and light both play a very important role in deter- 
mining the development and direction of growth of the 
sporophor es of many of the Agaricales, so that it 1s not sur- 
prising to find that the combined action of these two stimuli 
is necessary for the development of a perfectly formed 
sporophore. 
