CHESTNUT BARK DISEASE. 453 
than Diaporthe. It has two saprophytic or semi-parasitic 
relatives in this country, known as Endothia radicalis and 
Endothia gyrosa. The latter also occurs on chestnut, and the 
chestnut blight, being very similar morphologically, has been 
referred to it by the writer as a parasitic variety called Endo- 
thia gyrosa var. parasitica. Others have considered the two 
as entirely distinct species, and still others as forms so closely 
related as to be identical morphologically. 
(5) While no record, either here or abroad, has been found 
of any previous outbreak of the blight fungus, there have been 
reported at different times in the past century unknown chest- 
nut troubles in the southeastern United States that possibly 
may have been due to it. 
(6) The blight fungus has been considered by Metcalf as 
an importation from Japan, and by Shear as introduced from 
Europe, while the writer maintains that it is a native fungus, 
which, because of peculiar conditions detrimental to the host, 
has assumed unusual virulence and widespread prominence. 
(7) These conditions unfavorable to the host were in part 
the unusually severe winter of 1903-04, which injured trees in 
general in the northeastern United States, and after which 
the blight suddenly made its appearance, and in part the sub- 
sequent unfavorable seasons for trees, especially the last 
four or five years, when summer droughts were unusually 
severe. 
(8) If the writer’s conclusions are correct, then it is useless 
to try to make a widespread fight against the fungus, since it 
will, under conditions favorable to the host, return in time to 
its former inconspicuous parasitism. If they are incorrect, 
it is still a question whether or not the cutting out and 
quarantine method is effective and can be carried on so 
economically and extensively as to be of practical value. 
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