138 STEVENS: PREVALENCE OF ENDOTHIA GYROSA 
6 Quercus nigra : Le 
7 Quercus georgiana By die es 
sca 
52 100 150 BOO MILES 
Fic, 3. Ranges of several species of Quercus in the United States. Map pre- 
pared by W. H. Lamb. 
of the host species of E. gyrosa extend considerably north of the 
region where this fungus has been found they no longer predomi- 
nate. 
The relative importance of hosts of E. gyrosa among the nor- 
thern hardwoods is well brought out in a recent report by Froth- 
ingham (3, p. 6), in which the species comprising the northern 
hardwood forest are grouped according to their prevalence as 
characteristic, locally characteristic, or occasional. Of the hosts 
of E. gyrosa only beech appears among the characteristic and only 
