ENDOTHIA PARASITICA AND RELATED SPECIES. 23 
on Quercus alba and @. prinus, E. parasitica produced the typical 
mycelial fans. . 
Anderson (1, p. 14) considers that the occurrence of these fans 
is associated with the parasitic habit of the fungus. In his opinion 
single hyphe do not possess the power of penetrating the living cells, 
but the fungus grows on the injured and dead cells about a wound 
until a quantity of mycelium is accumulated, when it “en masse 
pushes through the living tissues of the bark.” This view is also 
held by Keefer (45, p. 193), who adds that “the action of the ad- 
vancing mycelial mats seems to be physical rather than chemical, 
and the cells are mechanically broken to pieces.” 
Rankin, however, states (62, p. 248) that “The host cells, just 
jn advance of the edges of the fan, are disintegrated and form a 
distinct gelatinous band, which can be seen with the naked eye.” 
This observation suggests to the writers that some toxic or enzymatic 
action upon the cells of the host probably occurs before the cells 
are actually invaded by the fungus hyphe. Careful investigation 
of this point should go far toward determining the causes of the 
parasitism of this fungus. Whatever the cause or function of these 
fans, they are very characteristic, and the writers have found them 
invariably in diseased material of Castanea in America, as well as 
in that from China and in two specimens of £. parasitica on Quercus. 
A similar mycelial formation, fanlike in form, is produced by 
Armillaria mellea in the bark of roots attacked by this fungus. Ex- 
cellent specimens of the Armillaria mycelial fans have been pre- 
sented to the writers by Prof. Wm. T. Horne, of the University of 
California. 
STROMATA. 
Under the name Melogramma gyrosum, in which they included 
specimens of both Endothia gyrosa and £. fluens, the Tulasnes (83, 
pp. 87-89) described the structure of Endothia in some detail. Their 
description was based chiefly on abundant local material of Z. fluens 
collected on Carpinus betulus L. during several years, but they also ; 
used material sent by Guepin from western France, pycnidial ma- 
terial on chestnut from Italy, American material sent by Schweinitz 
to Brongniart and preserved in the Paris Museum, and specimens 
from Carolina sent by Berkeley. According to the Tulasnes (83, 
p. 87)? the stromata are “developed singly and emerge gradually 
as so many scattered points with fibers radiating in all directions, 
soon swell into a yellowish cone, rupture the epidermis above them, 
1 Since this manuscript was completed a very similar mycelial formation has come to 
the writers’ attention. As figured by Nowell (50), pl. 1, Rosellinia pepo, when growing 
under the bark of lime trees, forms mycelial fans resembling those of Endothia parasitica, 
2The portions in quotations are rather free translations of the authors Latin. 
