Wayside and Woodland Trees: A pocket guide to the British sylva. Step Edward

(Cowthorpe Oak), with a much broader base. The thick rough bark is deeply furrowed in a large network pattern, which affords temporary hiding-places for insects. The branches are much given to turn and zig-zag from side to side—a character that makes them very useful in boat-building, as "knees" of various angles may be cut from them without having recourse to bending. The best knees are to be obtained from Oaks grown in the hedgerow.

      

Oak. A, female flower; B, male flowers.

      The Oak flowers in April or May, and the blossoms are of two distinct forms—male and female. The males are in little clusters, which are borne at intervals along a hanging stalk, two or three inches in length. They are green, and therefore inconspicuous; but examined separately, they will be found to have a definite calyx, whose margin is cut into an uncertain number (4-7) of lobes. There are no petals, but attached to the sides of the calyx there are ten stamens. The female flowers are fewer, and will be found on short erect stalks above the male catkins. Each female flower consists of a calyx, invested by a number of overlapping scales, and enclosing an ovary with three styles. The ovary is divided into three cells, each containing two seed-eggs. An acorn should therefore contain six kernels, but, as a rule, only one of the seed-eggs develops, though occasionally an acorn contains two kernels. The overlapping scales at the base of the female flower become the rough cup that holds the acorn.

      The Oak is subject to a considerable amount of variation, probably due to differences of situation, soil, etc., and some authors have sought to elevate certain of the varieties into species by giving them distinctive names. It does not appear to be certain, however, that these forms are at all constant, and they are connected by intermediate forms that make the identification of many individuals a matter of difficulty. In one of these forms (sessiliflora) the stalk of the acorns connecting them with the branch is very short, but the leaves have a distinct footstalk, from half an inch to an inch long. This form is more plentiful in the north and west, and is conspicuous in the Forest of Dean. A second form, known as pedunculata, has the leaf-stalk short or absent, the base of the leaf broad and somewhat heart-shaped, and the stalk upon which the acorns are borne very long. A third form (intermedia), commonly known as Durmast, has short leaf-stalks, short stalks to the acorns, and the under side of the leaf downy. Pedunculata is found more on the lower hills and the sides of valleys, whilst sessiliflora prefers higher ground, with a southern or western aspect.

       Pl. 4. Bole of Oak.

       Pl. 5. Flowers of Oak.

      The Oak is most abundant on clay soils, but is at its best when growing in deep sandy loam, where there is also plenty of humus. Its roots in such soil strike down to a depth of five feet, and therefore it thrives in association with Beech, whose roots are much nearer the surface, and whose fallen leaves supply it with humus.

      The Oak is more persistently attacked by insects than any other tree. One authority (Leunis) has tabulated the species that get their living mainly or entirely from their attacks on the foliage, timber, or bark, and they number about five hundred. With some species this warfare is waged on so extensive a scale, that in some years by early summer the Oaks are almost divested of their foliage, and a new crop of leaves becomes a necessity. But the reserve forces of the Oak are quite equal to this drain, and the tree does not appear to suffer, though a much less thorough attack would be serious to a Conifer. One of the worst of these Oak-spoilers—though it by no means restricts its energies to attacks on this tree—is the Mottled Umber Moth (Hibernia defoliaria), whose pretty caterpillars may be seen hanging by silken threads from the leafless twigs.

      A striking Oak insect is the Stag Beetle (Lucanus cervus), which, in warm evenings in the south of England, may be seen flying round the Oaks, the size and antler-like jaws of the male arousing feelings of respect in the minds of those who are not acquainted with its habits. The formidable looking "horns" are usually harmless. The beetle spends its larval stage in the wood of unhealthy Oaks, and, when mature, seeks his hornless mate among its foliage.

      Perhaps the most interesting of the Oak's pensioners to the woodland rambler will be the varied forms of gall on different parts of the tree. There is the so-called Oak-apple, of uneven surface and spongy to the touch, which certain people still wear on May 29th, in honour of Charles II.; the well-rounded hard Bullet-gall of Cynips kollari, the Artichoke-gall of Cynips gemmæ, the Spangle-galls of Neuroterus lenticularis, so plentiful on the back of the leaf, and the Root-gall of Biorhiza aptera. All these galls are abnormal growths, due to the irritation set up by the Gall-wasps named, when they pierced the young tissues in order to lay their eggs in them. Where any of these galls are perforated it may be known that the Gall-wasp whose grub fed within has flown, but where there is no such perforation the grub is still within, feeding upon the flesh of the gall, or in the chrysalis stage, awaiting translation to the winged condition.

      Several Oaks of foreign origin are also grown in our parks and open spaces; among them the Holm Oak (Quercus ilex) whose evergreen leathery leaves have toothed or plain edges, and occasionally the lower ones develop marginal spines, whence its name of Holm or Holly Oak. It is notable for retaining its lower branches, so that its appearance, as Loudon remarks, "even when fully grown, is that of an immense bush, rather than that of a timber tree." It is a native of Southern Europe and North Africa, and appears to have been introduced about the middle of the sixteenth century. It usually attains a height of from twenty to thirty feet, but occasionally specimens are seen up to sixty feet. It has a much thinner, more even bark than that of our native Oak, and of a black colour. The long brown acorns do not ripen until the second year.

       Pl. 6. Holm Oak.

       Pl. 7. Acorns of Turkey Oak.

      

      The Turkey Oak (Quercus cerris) is a much larger tree, attaining to similar heights to our British Oak, but easily distinguishable by its more pyramidal outline, and its attenuated leaves. The lance-shaped lobes of these are unequal, sharp, and angular; and the footless acorn-cups are covered with bristly or mossy-looking scales. The acorns, which are small and exceedingly bitter, rarely ripen till their second autumn. The whole tree—trunk, branches, and twigs—is of straighter growth than Quercus robur. It is a native of Southern Europe and the Levant, and was introduced about one hundred and seventy years ago.

      The spring rambler in the woods may come upon a party of woodmen stripping young Oaks of their bark, or felling them, whilst cylinders of separated bark rest across poles in the process of drying. This is the industry of barking for the purpose of the tanner. When the Oaks in a coppice are about sixteen years old they are most suitable for this purpose, the bark then containing a larger percentage of tannin than at any other period. The operation is best performed in May, when the sap is in flow, and should be completed between the first swelling of the leaf-buds and the unrolling of the leaves. If the weather is cold and damp the bark will peel the better, provided there is an absence of north or east winds. Before the tree is cut down the bole is stripped, the first ring being taken from just above the roots to a height of two and a half feet above. When the tree is felled, it is cut into lengths and the bark stripped from them; then all branches that are an inch or more in diameter are peeled. The bark is piled to dry for a couple of weeks, and is then broken into small pieces and sent away in sacks.

      It is not alone in the use of the bark that the tannic acid of the Oak is made evident; it is to the presence of this that the austerity of the acorn is due, and also the ink-producing properties of certain Oak-galls. Everything connected with the tree gets a roughness of flavour from this same principle. Even that remarkable fungus, the Vegetable Beef-steak, that may be found on old Oaks in autumn, is impregnated with it.

      Prior regards the name Oak (Anglo-Saxon ac) as originally belonging to the fruit,