Groom.—Remarks on the Oecology of Coniferae. 265 
regularly each year (as in the case of the oak attacked by the leaf-roller 
moth) and continue to exist. The larch, being deciduous, rather resembles 
the deciduous dicotyledon in this respect, for repeated partial defoliation 
by the caterpillars of the little moth Coleophora laricella does not cause 
its death. 
Bark-beetles easily cause the death of Conifers if the attack be severe 
or sustained ; whereas birches, ash-trees, and elms can endure for many 
years severe attacks from the familiar species of bark-beetles that infest 
them. In this respect the larch seems rather allied to the evergreen 
conifers. Cortical injury to the larch by the canker-fungus, Dasyscypha 
calycina , varies in its result, but in numbers of cases the tree can resist this 
fungus for more than sixty years. 
Even larvae tunnelling in the wood kill evergreen Conifers more readily 
than they do dicotylous trees. 
Finally, Colonel Prain informs me that in Calcutta Botanic Garden 
coniferous trees thoroughly shaken by the wind, though not uprooted, seem 
to die more readily than dicotylous tress. To what extent this is due to 
the evergreen character in a climatically deciduous region or to tardy 
replacement of the injured roots it is impossible to say. 
The causes of the greater vulnerability of the conifer are varied and 
perhaps partially obscure. When all the leaves of the tree are destroyed 
the evergreen Conifer loses what required years to produce and will require 
years to replace, and at the same time the tree is partially deprived of the 
assimilating organs required to manufacture the material for replacing the 
missing members. In addition, the coniferous plant is endowed with less 
power of replacing the missing leaves, as it has neither the wealth of 
dormant buds nor the power of emitting adventitious shoots possessed by 
a dicotylous deciduous tree. An exception to this rule prevails in the yew, 
which can withstand severe clipping, though this is fatal to most Conifers. 
It is worthy to note that evergreen Coniferae have a larger number of 
serious fungal and insect foes than have dicotylous trees in north-temperate 
regions. This may be wholly, or only partially, another method of stating 
the proposition that the Conifers are more readily killed or injured. 
To prove the statement I have drawn up lists of tree-attacking Fungi 
and insects from the recognized textbooks on the diseases of trees by 
Hartig, Von Tubeuf, and Judeich and Nitsche. 
I give below a table showing the number of Fungi attacking forest 
trees, first as given in Hartig’s ‘ Diseases of Trees’, and thus as enumerating 
the ones that were so obviously important as to be investigated first, and 
secondly, as given in Von Tubeuf’s ‘Diseases of Plants’. In my lists 
I originally grouped fungal diseases into four classes :— 
1. Those fatal to the tree. 
2. Those severe, and causing much injury to the living tree. 
