462 
THE DICTIONARY OF GARDENING, ` j : 
Oak—continued. 
seldom doing very great harm to the latter; yet even 
they may at times do great damage to Oaks, such as 
the larve of various moths (see Hybernia, Lackey 
Moth, Liparis, Orgyia antiqua, &c.) to the leaves; 
Cockchafer grubs, Mole Crickets, &c., to the roots; Bala- 
ninus nucum, or Nut-Weevil, in the fruit, Ke. It 
may, indeed, be said that no part of the tree is safe 
from the attacks of insect foes; but it is impossible 
here to do more than mention a few of the more in- 
teresting and important of these. Several beetles (see 
Tomicide), e.g., Platypus cylindrus, Xyleborus dryo- 
graphus, &., and some moths (see Goat Moth) bore 
into the wood, and render it unfit for use; but, for- 
tunately, they seldom attack healthy trees. As a pre- 
caution against them, all the dead trunks should be re- 
moved, and dead branches should be destroyed. The other 
moths above mentioned are hurtful by consuming the 
leaves of Oaks, Beech, and many other trees. But 
even more thorough in the extent of its ravages is a 
small moth (Tortriz viridana), which almost restricts 
itself to the common Oak. It reaches about zin. in the 
spread of the front wings, which are green. The larvæ 
live for a time in the buds, then in the leaves, and 
pupate in leaves spun together, or in the soil. In some 
seasons, and in certain localities, hardly a leaf is 
allowed to remain on the trees. Shaking the branches 
over sheets laid on the ground will cause the larvæ of 
all the moths to fall on to the latter, from which they 
may be swept up and destroyed. The same method may 
be employed for the capture of various kinds of small 
beetles, chiefly Weevils, that gnaw the leaves and buds, 
as well as of Cockchafers, which, at times, do consider- 
able damage to the trees. 
The leaves are frequently mined by the larve of small 
moths and beetles, but the injury from this cause is 
too slight to call for discussion at present; and, for 
the same reason, the larve that feed in the buds may 
be passed over in silence. Among the more frequent 
causes of injury to the acorns is the beetle Balaninus 
nucum (see Nut-Weevil). ‘Numerous species of Green 
Fly attack the Oak, and, at times, must weaken the 
trees very greatly, covering the lower leaves with honey- 
dew, among which grows the Fungus Capnodium quer- 
cinum (see Oak Fungi), which may, in some cases, 
prove hurtful to the trees. But, of all the insects that 
attack Oaks, probably the most striking, in respect to 
the effects produced by them, are the makers of the 
various Galls so frequent and so noticeable on Oak 
trees. See Oak Galls. 
OAK APPLE. See Galls and Oak Galls. 
OAKESIA (of Tuckerman). A synonym of Corema. 
(of Watson). Included under Uvularia 
(which see). 
OAK FERN. See Polypodium Dryopteris. 
OAK FUNGI. The species of Fungi that live upon 
the common Oak are numerous; but by far larger 
proportion either do comparatively little injury, Or make 
their appearance only on dead parts of the trees; e.g., 
on bark or wood of dead branches, or on leaves or 
- acorns. Many of the species are very minute, but only 
a few of the more injurious will be mentioned here. 
Those of chief importance belong to the Hymeno- 
mycetes (see Mushrooms), and, for the most part, to 
the ov Polyporus, which has pores instead of gills on 
e lower surface of the cap, or spore-producing struc- 
The following are among the more noteworthy 
, inasmuch as their mycelium traverses the living 
of the Oak, and withdraws the nourishment from 
cells of the wood, which, in consequence, becomes 
and brittle. 
to a breadth of several Se Of Polyporus, 
The cap, in most of the species, 
Oak Fungi- continued. : og 
several species attack living wood of Oak, e.g., P. 
dryadeus, P. sulphureus, P. igniarius, and P. inty- 
baceus; so also does the nearly-allied Fistulina hepa- +- 
* 
* 
Ayk 
tica, or Beefsteak Fungus. In each case, the mycelium 
of the Fungus usually gains entrance by the uncovered 8 
end of a branch, or a wound, and spreads through the 6 
wood cells, Careful pruning, and protection of wounds Ps 
by tar, or some other dressing, are of very great service — 
in preventing the entrance of mycelium, and the conse- 
quent development of the Fungus, with its disastr 
results to the trees. The methods of pruning, and er 
protecting wounds, cannot be treated of under this 
head, but will be found fully described in this work under * 
the appropriate headings. Trees suffer much injury i x 
from Fungi in their roots, which become attacked by 4 
the mycelium spreading in the soil from adjoining roots 4 
of dead trees; hence, care should be taken to remove, 
as far as possible, all decaying wood from soil in thas 
neighbourhood of healthy trees, lest the Fungi sho 
extend to the roots of the latter, and, after a tine, < 
cause their destruction. Trees, when badly R DET 3 
by these Fungi, should be cut down and destroyet 
prevent the spread of the Fungi to healthy trees. 
Polyporus. s 
A soot-like crust very frequently covers the leaves o 1 
Oaks, as well as of many other trees and shrubs. When K 
examined microscopically, it is seen to be formed of 
cells and threads of a Fungus, belonging to a group ; 
included under the name Fumago, called also, when “= 
fully developed, Capnodium. In Capnodium, the spores 
for reproduction are produced in the interior of ` 
larger cells (asci), many of which are inclosed in a 
globular or flask-shaped vessel (perithecium), of micro- 28 
scopic size; but this stage of development is not often * 
met with. The Fumago stage is much the more co a 
mon. In this, the reproductive cells are separated 8 
the tips of threads on the exposed surface, or are pro- ; 
duced in minute flask-like perithecia, but not in asci. a a a 
The crusts are much like soot in general appearance, * . 
like it, resting only on the upper surface of the leaves. 
They have frequently been attributed to injury from 
smoke, leading more than once to lawsuits for com- | 
pensation for such alleged injury. The microscope abate oy 
the cell walls to be dark brown. * 
The Fungus is readily removable from the . * : 
rubbing the surface. It does not seem to derives, 
nourishment from them—at least, to any marked extent 
—but feeds in large degree, probably, on the honeydew 
excreted abundantly by various kinds of Aphides, or 
Green Flies. As these insects live.on the lower surface 
of the leaves, their excretions fall on the upper surface 
of leaves below them, which explains the presence of 
the Fungus on that surface. If present only in small 
amount, the crust does not seem to do much injury to wig ; 
the trees; but when thik, it partially chokes the leaves, 
and cuts off the light from them, so that they become 
sickly, and fail to nourish the trees. This seldom occurs 
before autumn, which is fortunate, as there is hardly 
any practicable method of removing Fungi from trees 
such as Oaks. The species found on Oak has received 
various names, that generally adopted being Capnodium 
quercinum, ath, 
OAK GALLS. Very noticeable, because of their size, 
the peculiarities of their forms and colours, and the dis- 
tortions and alterations that they occasionally produce 
on various parts of Oaks, are the Galls, so frequently see 
by even the least observant spectator who passes an Oa! 
tree in autumn. The development of the Galls, and of 
their makers, is now believed to be very peculiar in 
certain respects in the case of most of them; but only 
a few of them are here selected as examples. Galls are 
new structures budded out from stems, leaves, or other 
parts of plants, under the influence of a stimulus applied 
r 
