Cork is the external bark of a species of oak (Quercus suber) which grows in Spain, Portugal, and other southern parts of Europe and in the north of Africa, and is distinguished by the great thickness and sponginess of its bark, and by the leaves being evergreen, rectangular, somewhat oval, downy underneath, and waved. The outer bark falls off of itself if left alone, but for commercial purposes it is stripped off when judged sufficiently matured, this being when the tree has reached the age of from fifteen to thirty years. The first stripping yields the coarsest kind of bark. In the course of eight or nine years, or even less, the same tree will yield another supply of cork of better quality, and the removal of this outer bark is said to be beneficial, the trees thus stripped reaching the age of 150 years or more. The bark is removed by a kind of axe, parallel cuts being carried round the tree transversely and united by others in a longitudinal direction, so as to produce rectangular sheets of bark. These vary in thickness between 2 mm and 7 mm. Care must be taken not to cut into the inner bark, or the tree would be killed. The pieces of cork are flattened out by heat or by weights, and are slightly charred on the surface to close the pores.
Cork is light, elastic, impervious to water, and by pressure can be greatly reduced in bulk, returning again to its original size. These qualities render it peculiarly serviceable for the stopping of vessels of different kinds, and formerly for floats, buoys, swimming-belts or jackets, artificial limbs, etc. Corks for bottles are cut either by hand or by means of a machine. The best corks are cut across the grain. Research Cork
Coccus is a genus of insects of the order Hemiptera, family Coccidae, or scale-insects. The males are elongated in their form, have large wings, and are destitute of any obvious means of suction; the females, on the contrary, are of a rounded or oval form, about an eighth of an inch in length, have no wings, but possess a beak or sucker, by which they suck up the juices of the plants on which they live. At a certain period of their life the females attach themselves to the plant or tree which they inhabit, and remain thereon immovable during the rest of their existence. In this situation they are impregnated by the male; after which their body increases considerably, in many species losing its original form and assuming that of a gall, and, after depositing the eggs, drying up and forming a habitation for the young. Some of these insects are troublesome in gardens, plantations, and hot-houses, while others are of great value. for example, kermes, cochineal, lac-lake, lac-dye, and gum-lac are either the perfect insects dried, or the secretions which they form.
Kermes consist of the dried females of Coccus ilicis, found in great abundance upon a species of oak (Quercus coccifera), a native of the Mediterranean basin, and gathered before the eggs are hatched. It was known as a dye-stuff in the earliest times, but has partly fallen into disuse since the introduction of cochineal. Cochineal consists of the bodies of the females of the Coccus cacti, a native of Mexico, which feeds on various species of cactus, particularly on one called nopal (Opuntia cochinillifera). Research Coccus
Durmast is a species of oak, Quercus sessiliflora, or according to some, Quercus pubescens, so closely allied to the common oak (Quercus robur) as to be reckoned only a variety of it. Its wood is, however, darker, heavier, and more elastic, less easy to split, not so easy to break, yet the least difficult to bend. It is highly
valued, therefore, by the cabinetmaker and formerly also by builders. Research Durmast
Gall-fly is a name for several hymenopterous insects of the family Cynipidae, which form galls, each species preferring a different plant. The gall is due to an irritating fluid which the insect deposits on the plant along with its egg. The large galls at the base of oak leaves are produced by the Cynipsquercus baccarum, a fly of a brown colour, with blade antenna, chestnut-brown legs, and white wings. The small galls on the under surface of oak leaves are due to another species, Cynipsquercus folii, those on the stems of oaks to Cynips terminalis. Research Gall-fly
A gall (also known as a gall-nut or nut-gall) is a growth caused on plants of various kinds by parasitic mites (Phytoptidae). The galls of commerce are produced by a species of Cynips (Gall-fly) in the tender shoots of the Quercus infectoria, a species of oak abundant in Asia Minor, Syria, Iraq, etc. They are spherical and tubercular, and vary in magnitude from the size of a pea to that of a hazel-nut. White, green, and blue varieties are recognized, the latter kinds being the best. They are inodorous, but are strongly astringent from the tannin and gallic acid which they contain, and which are their chief products. Gall-nuts were extensively used in dyeing and in the manufacture of ink, and they were also frequently used in medicine. They were chiefly imported from Aleppo, Tripoli, and Smyrna. The Chinese galls, or woo-pei-tsze, differ from the foregoing in that they are really an unusually massive kind of crust or cocoon, such as the aphides form on the surface of a plant; the tissues of the plant are not affected. After the opening of the Japanese ports these were imported in considerable quantities to Britain. Research Gall
Holm-oak (QuercusIlex) is a shrub-like tree native to Mediterranean countries with holly-like leaves. In its native countries it attains a considerable size and age, but in Britain it forms an ornamental evergreen bush of from six to nine meters high, seldom becoming single-stemmed. Research Holm-oak
The oak is a tree of the genusQuercus, family Fagaceae, family Cupuliferae. They have a three-celled ovary and bear a round nut called an acorn. The timber of the British oak - the Pedunculate Oak or Common Oak (Quercus robur) is very hard, though prone to twisting, and was formerly used for building warships. Research Oak
The Oak Eggar (Lasiocampa quercus) is a moth of the family Lasiocampidae with a wing span of between 45 and 75 mm found in Europe and Asia. The male moth flies during the day, the female late in the afternoon and at night, both sexes flying from June to August. Research Oak Eggar
The pedunculate oak (Quercus robur) or common oak is a large deciduous tree of the family Fagaceae with a short trunk from which large branches arise to form a massive, round-topped crown. The brownish-grey bark is smooth at first, and later deeply fissured. The leaves are alternate, leathery, dark- green in colour, lobed and have auricles at the base. Research Pedunculate Oak
Abbreviations
Research Cork
