302 
Mycologia 
as causing a disease of Canada poplars near Turin and in other 
localities in Italy. In 1910 (7: 285-287) and 1911 (8; 325-337) 
he published additional articles, which contain the results of a 
lengthy investigation of both the disease and its causal fungus. 
He reported proof both by cultural studies and by inoculations 
that Dothichiza popiilea Sacc. & Briard is the pycnidial form of 
the ascomycete Cenangium populneum (Pers.) Rehm. He found 
that the fungus is the cause of a very serious disease of poplars, 
especially the Canada poplar, in various parts of Italy. 
From the foregoing data, it appears quite possible that Dothi- 
chiza popiilea has been imported, though not very recently. A 
great quantity of nursery stock has been brought to this country 
from Europe, and the fungus could easily have been brought in 
previous to the enforcement of the present inspection laws. 
On the other hand, the fact that this disease has not been re- 
ported previously from this country by any of the state patholo- 
gists and that earlier specimens of Dothichiza popiilea have not 
been collected by the pathologists of the United States Depart- 
ment of Agriculture indicates that it is a somewhat recent disease 
in the United States. 
This assumption is further strengthened by the absence of 
Dothichiza popiilea from the exsiccati that have been collected in 
this country and the fact that there is apparently no mention of 
it in our literature. 
Description of the Disease Caused by Dothichiza populea 
Dothichiza popiilea attacks the trunk, limbs, and twigs of both 
the black and the Canada poplars. It primarily causes the for- 
mation of cankers, which at first appear as depressed, slightly 
darkened areas in the bark, usually on the trunk around the base 
of a small limb or twig {pi. ip4, f. 2, j). The cambium is killed 
and turns brown {pi. 795, /. 3). Pustules of the fungus soon 
appear on the canker, giving the surface a roughened appearance 
{pi. IQ4, f. 2, 3). In trees that have become well established in 
the soil a marked resistance of the host to the fungus frequently 
takes place. In such cases the growth of the fungus is checked, 
the canker limited to a small patch of varying shape and size, and 
the bark is frequently cracked at the edge of the canker by the 
