Dasyscypha resinaria causing Canker Growth on Abies balsamea in 
Minnesota 
By ALEXANDER P. ANDERSON 
(WiTH PLATES I AND 2) 
In the fall of 1896, while collecting plants in the vicinity of 
Walker, on Leech Lake, northern Minnesota, the writer noticed 
that the trunks and larger branches of Adies balsamea, which grows 
abundantly in the bogs around this place, were affected to a great 
extent with some fungus or insect, producing numerous canker-like 
growths and swellings on the stems. This was true especially of 
the lower part of the tree trunks, and around the branches that had 
been shaded out and had died on account of an insufficient amount 
of light. On some trees almost every knot and dead branch was 
surrounded by one or more of these canker swellings, the canker 
not infrequently extending all around the tree trunk, or branch 
(fig. 2). When younger stems or branches were affected in this 
way the portion above the canker, and often the whole stem, had 
been killed by the girdling (jig. 7). 
The trees and cankers were carefully examined, to see whether 
‘the cause of the deformation might not be due to insects, like the 
one causing the common tumors and “ witch-brooms”’ on Picea 
nigra * which also grows in the bogs of northern Minnesota. No 
Chermes nor other insect of any kind was present on the affected 
trees, nor could any indications of any be found, either on the 
surface of the trees, or on the inside of the bark and wood. 
The rough bark of the canker was found to have on it, numer- 
ous ascomata (jig. 3) which were very similar to those of Dasys- 
cypha calycina (Schum.) Fuckel (D. Willkomii Hartig), the com- 
: * These ‘* witch-brooms’”’ on Picea nigra sometimes become a meter or more in 
diameter and are usually spherical, when full grown. They are caused by some 
Species of Chermes—probably Chermes abictis. Compare von Tubeuf, Forst-naturw. 
Zeitschr. 2: 76. pl. 5. 1893; Anderson, A. P,, Bot. Gazette, 24: 312. 1897; and 
Brodie, W., The spruce Gall-louse, Ontario Department of Agriculture Bureau of 
Forestry, Toronto, May 1, 1893. In the last, mention is made of Chermes abietis as 
occurring on Picea nigra and Abies balsamea in Canada. 
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