'e48 BULLETIN 347 
Cankers on smooth bark are especially conspicuous (Plate XXXVI, 
frontispiece). They can be seen for a long distance because of their 
reddish tinge in contrast to the healthy green bark. The cankers are 
either sunken or swollen diseased areas of the bark (Plate XX XVII). 
They occur on branches of all sizes— only rarely, however, on first- 
year twigs. The usual shape of the canker is ellipsoidal, being longer 
cere: 
Fic. 81. — Chestnut woodland devastated by the canker. Photograph taken in midsummer 
in the direction of the long axis of the limb. The margin of the canker 
is usually fairly regular, but it may be irregular. 
Metcalf (1914) says the cankers formed on the Chinese chestnut become 
deeper year by year as healthy wood is formed about them, thus causing 
a condition similar to the European apple-tree canker. 
Usually about a month after inoculation the bark of the affected area 
becomes covered with numerous small pimples. Under moist conditions, 
following rains, long, twisted, yellow tendrils are extruded from the 
