132 STEVENS: PREVALENCE OF ENDOTHIA GYROSA 
tain. Its growth in these localities was nearly, if not quite, equal 
to that at more southern points. 
The effect of abundant moisture is readily seen from the fact 
that at Concord, Williamstown, and two stations, S 3 and C, on 
Overlook Mountain, stromata developed in 1915 from inoculations 
which had shown no growth in 1914; as well as by the fact that at 
Hartford, Connecticut, stromata developed abundantly during the 
summer of 1915 from inoculations which during the summer of 
1914 showed only a few scattered stromata. As the weather 
conditions of the two summers in these localities have been 
discussed in detail by the writer elsewhere (10) it may merely be 
stated here that there was little difference in the temperature 
but that the rainfall of 1914 was much below normal; that of 
1915 well above normal. 
The importance of the condition of the host in the growth of 
Endothia gyrosa was best seen at Charlottesville, Virginia,* where 
the small tree which was inoculated gradually died from the effect 
of the cuts and the fungus developed rapidly and produced stro- 
mata for a considerable distance above and below the point of 
inoculation. The growth of the fungus on this tree was much 
greater than that onany of the trees which survived the wounds 
made by inoculations. The peculiar relations between this fungus 
and its host have been referred to elsewhere (8). In general it has 
been observed that tissue injured by cuts or bruises in such a way 
that it does not dry out immediately but remains in a living condi- 
tion for some time is the most favorable place for the development 
of this fungus. Such a condition is found on the stubs of cut 
limbs, on bruised or broken trunks, and especially on exposed 
roots which have been injured by tramping of cattle or by other 
means. This habit of the fungus seems to materially affect its 
distribution. 
CLIMATIC RELATIONS 
Temperature-—The range of temperature favorable for the 
growth of E£. gyrosa in artificial media seems to be almost identical 
with that of E. parasitica (8). The writer has recently demon- 
strated (10) that during the years ending in May and August, 
* The inoculations and some of the observations at this point were made by 
G. F. Gravatt. 
