B50 BULLETIN 347 
tive brown hue. When the fungus affects rough bark, no shrinking 
nor swelling nor change in color is evident, and it is only when the 
yellow tendrils, or later the brown pustules, are produced in the 
crevices of the bark that an outward indication of the diseased area 
appears (Plate XX XVIII, Fig. 3). 
By examining the character of 
A .| the destruction cf the bark one 
LONE may determine other diagnostic 
characters. When the bark is peeled 
from the edge of a canker it is found 
to be flaked with tawny, fan-shaped 
areas, which, once seen, are easily 
recognized (Plate XXXIX). The 
invaded tissue is changed to a light 
sienna brown and appears in marked 
contrast to the normal light-colored 
bark. Thick bark that is affected is 
reduced to a mass of shreds, which 
are a uniform dark brown in color. 
The first layers of wood and the 
medullary rays also turn brown 
under the cankered area. 
ETIOLOGY 
Name of the causal organism 
It has been proved by Murrill 
(1906, a, b, and c) that the Endothia 
canker of chestnut is produced by a 
fungus which he refers to the genus 
Diaporthe, of the Sphaeriales. Believ- 
ing that it had not been previously 
described he gave it a new specific 
name, parasitica, recalling its de- 
structive parasitic habit. 
Pe, S37 Tie las ten ded fr ‘ech (3907) declares that it be 
off in patches and exposing the wood longs among the Hypocreales in the 
genus Valsonectria, and proposes 
the combination Valsonectria parasitica (Murr.) Rehm. 
Clinton (1909:888) quotes Farlow as stating that ‘“ it comes more 
naturally under the genus Endothia, and is closely related to E. gyrosa.” 
The latter is a saprophytic species which, as limited by Saccardo, was 
first described from North Carolina by Schweinitz in 1822 as Sphaeria 
