CANKER GROWTH ON ABIES BALSAMEA 33 
in the wood of branches of A. pectinata, produced experimentally 
by Nottberg * who fractured the branches by partly bending them. 
The characteristic canal chains were formed in the wood near the 
fracture, three months after the wound had been made. 
Hartig + found the same pathogenic resin-canal chains in the 
wood of trees of Adies pectinata that had been injured by light- 
ning. 
Resin-canals in the wood of species of Ades appears to be not 
an uncommon occurrence. They are formed only when the wood 
has been wounded mechanically in some way or when it becomes 
hypertrophied by the presence of certain fungi at the cambium. 
PARASITISM OF DASYSCYPHA RESINARIA 
Although the writer has had no opportunity to make infection 
experiments with a view to determine for a certainty that the can- 
kers formed on the trunks and branches of A. da/samea are caused 
by D. resinaria, there can be little doubt but that they are caused 
by this fungus, which is always found on the bark of the canker 
spots only and nowhere else on the trees. 
Like the European larch canker Dasyscypha, Dasyscypha 
resinaria fruits on the canker bark after the branch or stem af- 
fected has been killed. As far as was possible to make out, this fruit- 
ing on the dead stems continues only for one season after the 
stems have been killed by the parasite. Dead branches which 
have dropped from the tree have no ascomata on them excepting 
on the canker spots, and on these only when the branch has 
dropped off within a year previous. 
The absence of insects and the presence of the mycelium in 
the bark, as well as at the cambium of the canker; also the ab- 
sence of the ascomata on the normal bark of the living tree, as 
well as on stems that have been dead for more than one year, 
Seems, at present, to be sufficient evidence for including Dasyscypha 
resinaria among the parasitic species of this genus. The infection 
takes place, as a rule, around the base of the imperfectly self- 
* Nottberg, Dr. P., Experimental-Untersuchungen Uber die Entstehung der Harz- 
gallen und Verwandter Gebilde bei Unsere Abietineen. Zeitschr. Pflanzenkrankheiten, 
7+ 142. 1897. Alsoin Archiv der Pharmacie, 235: 256. 1897. 
* Hartig, Dr. R., Untersuchungen iiber Blitzschlage in Waldbaiumen. %Forst. na- 
turwiss, Zeitschrift, 6: 1 50. 1897. 
