76 BULLETIN 380, U. S. DEPARTMENT OF AGRICULTURE. 
slight differences, as indicated in the tables of measurements and 
ratios. 
Numerous cultures of all the species on a variety of media show 
that each species has constant and distinctive characters of growth 
and color. 
All the species grew equally well in light or darkness, and no de- 
cided differences in temperature relations have been demonstrated. 
The species appear to have well-defined geographic limits of 
distribution, which have been approximately determined for the 
American species. The distribution of the species does not coincide 
with that of the hosts, but seems to be determined in part by soil 
and climatic conditions, 
Endothia fluens has the widest distribution, being frequent and 
widely distributed in Europe and the eastern United States, and also 
occurring in Asia. 
Endothia parasitica is evidently of oriental origin. Specimens 
have been received from five rather widely separated localities in 
China and from two localities in Japan. In the eastern United 
States it is now abundant from Maine to North Carolina and is 
rapidly spreading south and west. It has already destroyed most 
of the chestnut trees within a radius of 100 miles of New York City. 
The species have rather definite host relations. 
Endothia gyrosa has been found on five genera of plants, viz, Cas- 
tanea, Fagus, Liquidambar, Quercus, and Vitis. 
Endothia singularis occurs, so far as known, only on Quercus 
species. 
Endothia fluens has been found in America only on Castanea and 
Quercus, but in Europe it occurs on Alnus, Carpinus, Castanea, 
Corylus, Quercus, and Ulmus, and has been reported on Aesculus, 
Fagus, and Jugians. 
Endothia fluens mississippiensis has been found only on Castanea 
and Quercus. 
E'ndothia tropicalis is known only on Elaeocarpus. 
Endothia parasitica has been found on Acer, Carya, Castanea, 
Quercus, and Rhus, but at present is only known as a serious para- 
site on Castanea. 
Upon the American species of Castanea it is actively parasitic 
under all the conditions of soil and climate observed. Oriental 
species of chestnut are more or less resistant to the disease both in 
America and their native homes. 
None of the species except Hndothia parasitica has thus far been 
found to be actively parasitic. 
