Although the cherry is without wings or a flying-machine of its own, it is rich enough to employ the rarest transportation in the world. With attractively colored and luscious pulp it hires many beautiful birds to carry it to new scenes. On the wings of the mockingbird and the hermit thrush,—what a happy and romantic way in which to seek the promised land!
Many kinds of pulp-covered seeds that are attractive and delicious when ripe are unpleasant to the taste while green; this protective measure guards them against being sown before they are ready or ripe. The instant persimmons are ripe, the trees are full of opossums which disseminate the ready-to-grow seeds; but Mr. 'Possum avoids the green and puckery persimmons!
The big tree is one of the most fruitful of seed-bearers. In a single year one of these may produce some millions of fertile seeds. These mature in comparatively small cones and, each seed being light as air, they are sometimes carried by high winds across ridges and ravines before being dropped to the earth.
The honey locust uses a peculiar device to secure wind assistance in pushing afar its long, purplish pods with their heavy beanlike seeds. This pod is not only flattened but crooked and slightly twisted. Dropping from the tree in midwinter, it often lands upon crusted snow. Here on windy days it becomes a kind of crude ice-boat and goes skimming along before the wind; with its flattened, twisted surface it ever presents a boosting-surface to the breeze.
The ironwood tree launches its seeds each seated in the prow of a tiny boat, which floats or careers away upon the invisible ocean of air, sinking, after a rudderless voyage, to the earth. The attachment to some seeds is bladder- or balloon-like; tied helplessly to this, the seed is cast forth briefly to wander with the wandering winds.
The linden, or basswood, tree uses a monoplane for buoyancy. The basswood attaches or suspends a number of seeds by slender threads to the centre of a leaf; in autumn when this falls it resists gravity for a time and ofttimes with its clinging cargo alights far from the tree which sent it forth.
Burr- or hook-covered seeds may become attached to the backs of animals and thus be transported afar. One day in Colorado I disturbed a black bear in some willows more than a mile from the woods; as he ran over a grassy ridge three or four pine cones that had been hooked and entangled in his hair went spinning off. Seeds sometimes are internationally distributed by becoming attached by some sticky substance—pitch or dried mud—to the legs or feathers of birds. Cottonwood seed often has a long ride, though generally a fruitless one, by alighting in the hair of some animal. Sometimes a cone or nut becomes wedged between the hoofs of an animal and is carried about for days; taken miles before it is dropped, it grows a lone tree far from the nearest grove.
Though the witch-hazel is no longer invested with eerie charms, it still has its own peculiar way of doing things. It chooses to bloom alone in the autumn, just at the time its seeds are ripe and scattering. Assisted by the frost and the sun, it scatters its shotlike seeds with a series of snappy little explosions which fling them twelve to twenty feet from the capsule in which they ripen.
The mangrove trees of Florida germinate their seeds upon the tree and then drop little plants off into the water; here winds and currents may move them hither and yon as they blindly explore for a rooting-place.
The cocoanut tree covers its nuts with a kind of "excelsior" which prevents their breaking upon the rocks. This also facilitates the floating and transportation of the nut in the sea. When the breakers have flung it upon rocks or broken reefs, here its fibrous covering helps it cling until the young roots grow and anchor it securely.