Page:TheTreesOfGreatBritainAndIreland vol01.djvu/84

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The Ginkgo when young is pyramidal in habit, with slender, upright branches: older, it becomes much more spreading and broader in the crown. It attains a height of 100 feet and upwards, with a girth of stem of about 30 feet. Bark: grey, somewhat rough, becoming fissured when old.

Leaves: deciduous, scattered on the long shoots, crowded at the apex of the short shoots, which grow slowly from year to year, their older portions being covered with the leaf-scars of former years. The short shoot may, after several years, elongate into a long shoot bearing scattered leaves. The leaves are stalked, and unique in shape amongst trees, recalling on a large scale the pinna of an adiantum fern; they show much variation in size (2–8 inches in breadth) and in margin, but generally are bilobed and irregularly crenate or cut in their upper part. There is no midrib, and the veins, repeatedly forking, are not connected by any cross veinlets. The stomata are scattered on the lower surface. In the bud the leaves are folded together and not rolled up, as in the crozier-like vernation of ferns.

Flowers and fruit: see description of the genus.

The drupe-like seeds have a fleshy outer covering of a bright orange colour when ripe, and when they fall upon the ground, this bursts and emits an odour of butyric acid which is very disagreeable. They are imperfectly developed as they fall, though apparently ripe; and the fertilisation of the ovule and the subsequent development of the embryo occur while they are lying on the ground during winter. The kernels^are edible, being known to the Chinese as pai-kuo (white fruits), and are sold in most market towns of China. They are supposed to promote digestion and diminish the effects of wine-drinking; and are eaten roasted at feasts and weddings, the shells being dyed red.

Fruit-bearing trees are now common in Southern Europe; but no fruit, so far as we know, has ever been produced in England. The well-known tree at Kew is a male, and produces flowers freely in exceptional years, e.g. in 1894, supposed to be due to the fact that the preceding summer was remarkably warm, with continual sunshine.

Extraordinary cases of abnormal formation of fruit have been observed in Japan. Shirai described and figured in 1891 fruit which was produced on the surface of ordinary leaves of the tree. Fujii has studied since then the various stages of the development of ovules and of pollen sacs upon leaves. The so-called aril of the fruit is considered by him to represent a carpel, as he has observed transitional stages between the ordinarily shaped aril and a leafy blade bearing ovules.