Because of its beauty and interest the plant is now widely distributed under cultivation, and is available for study almost as freely as the other types of living Gymnosperms already mentioned, so that but a short summary of its more important features is needed here. Old plants, such as can be seen growing freely in Japan (in Kew Gardens there is also a fine specimen), are very tall handsome woody trees, with noble shafts and many branches. The leaves grow on little side shoots and are the most characteristic external feature of the tree; their living form is illustrated in fig. 66, which shows the typical simple shape as well as the lobed form of the leaf which are to be found, with all intermediate stages, on the same tree. No other plant (save a few ferns, which can generally be distinguished from it without difficulty) has leaves at all like these, so that it is particularly easy to identify the fossil remains, of which there are many. [Illustration: Fig. 66.—A, Tuft of _Ginkgo_ Leaves, showing their “maidenhair”-like shape. B, Single deeply-divided Leaf to be found on the same tree, usually on young branches.] The wood is compact and fine grained, the rings of secondary tissue being developed from a normal cambium as in the case of the higher Gymnosperms, and the individual tracheæ have round bordered pits. There are small male cones, but the seeds are not borne in cones. They develop on special stalks on which are no scales, but a small mass of tissue at the base of the seed called the “collar”. Usually there are two young ovules, of which often only one ripens to a fleshy seed, though both may mature. [Illustration: Fig. 67.—Ripe Stage of _Ginkgo_ Seeds attached to their Stalk. _c_, “Collar” of seed.] The ripe seed reaches the size shown in the diagram, and is orange coloured and very fleshy; within it is a stone encasing the endosperm, which is large, _green_, and starchy, and contains the embryo with two cotyledons. This embryo is small compared with the endosperm, cf. fig. 57, p. 76, which is somewhat similar to that of _Ginkgo_ in this stage. Of the microscopic characters of the reproductive organs the most remarkable is the male cell. This is not a passive nucleus, as in the plants hitherto considered, but is an _actively swimming_ cell of some size, provided with a spiral of cilia (hairlike structures) whose movements propel it through the water. In the cavity of the unripe seed these swim towards the female cell, and actively penetrate it. The arrangements of the seed are diagrammatically shown in fig. 68, which should be compared with that of _Cycas_, fig. 76, with which it has many points in common. [Illustration: Fig. 68.—Section through Seed of _Ginkgo_