CHESTNUT BARK DISEASE. 417 
while E. gyrosa occurs south of this common area and the chest- 
nut blight north of it. (4) We have previously had serious 
troubles of chestnut trees in this country, and there seems to have 
been a continued northward movement of these, culminating in 
the recent trouble in the northern limit. While the chestnut blight 
has been definitely connected only with this last trouble, the pre- 
vious ones have never been really explained. (5) The sudden- 
ness, etc., of the recent blight outbreak has been adequately 
explained by the writer through the unusual environmental con- 
ditions that have weakened the chestnuts in the general regions 
where the outbreak has occurred. (6) The fact that the chestnut 
blight fungus was never reported before this outbreak is no more 
difficult to explain than the fact that E. gyrosa had never been 
reported on chestnut in this country until by the writer a year 
ago, and yet this is a native fungus widely distributed on chestnut 
in the South, and has been known there on other hosts since 1822, 
when described by Schweinitz. They both were, in fact, merely 
overlooked on the chestnut. (7) Our cultures of E. gyrosa vary 
more from their normal type than do those of the variety 
parasitica, and some of these have varied somewhat toward the 
variety parasitica type. This, however, may have been due in 
part to bacterial contamination, etc. 
AMERICAN SPECIES OF ENDOTHIA. 
Various Species. It has been agreed among those who have 
recently studied the blight fungus from a systematic standpoint 
that it belongs under the genus Endothia rather than under 
Diaporthe, and is at least very closely related to the American- 
European species Endothia gyrosa. So far there have been 
described under the genus Endothia comparatively few species. 
Fries, who founded this genus, apparently considered Sphaeria 
gyrosa as the type, but did not give a very complete generic 
description. As understood to-day, however, Endothia has quite 
distinct generic characters. Of the species other than Endothia 
‘gyrosa and the chestnut blight, there have been found in North 
America Endothia Parryi (Farl.) Cke., on Agave sp., Endothia 
longirostrata Earle, on the bark of fallen trees from Porto Rico, 
and Endothia radicalis (Schw.) Farl., on Quercus, etc., chiefly 
from the Southern states. 
