THE LARCH CANKER 75 
rise to most of the serious cankers on main trunks. The 
third is less important, since it only affects trees which are 
being killed out through lack of light. The importance of 
wounds has been over-estimated by most previous writers. 
Contributory causes, rendering the tree more liable to 
canker, are any agencies which cause wounds, damp stagnant 
atmosphere, and poor badly-drained soil. Pure larch 
plantations are more liable to the disease than those where 
the trees are intermixed with hardwoods. In general it 
may be said that any conditions which are prejudicial to 
the vigorous growth of larch are favourable to the spread 
of the disease. 
Healthy plantations can best be grown by selecting sites 
where all the conditions are favourable to larch growth, 
but a treatment has been suggested whereby it may become 
possible to grow sound trees where canker has usually been 
epidemic. By the pruning of branches it is hoped that 
infection from these members may be prevented. 
ON THE Synonymy oF Dasyscypha calycina, (Schum.) 
Fuck. 
The literature of larch canker has become much confused 
by the variety of names which have been applicd to the 
fungus causing it. 
Berkeley (1859) called it Peziza calycina; Willkomm 
(1867) confused it with a somewhat similar member of the 
Basidiomycetes, Corticium amorphum, and called it by that 
name; Hoffmann (1868) corrected this error, and adopted 
the same name as Berkeley; and Hartig (1880) said that 
the fungus showed microdimensional differences from 
P. calycina, and instituted a new name, Peziza Willkommi. 
Most English mycologists, however, have refused to adopt 
this new name, maintaining that the conventions of nomen- 
clature demand that it should be called Dasyscypha calycina. 
This confusion has arisen from the fact that there are 
three or four different species of Dasyscypha which are 
indistinguishable with the naked eye or a pocket lens, and 
