The small, single-seeded fruits of dandelions and thistles each have their own silky parachute that carries them some way from the parent plant. Conifers, such as pines and spruces, have light, papery- winged seeds. The wings of maple and sycamore fruits keep the nut-like seeds aloft for some time as they gently spiral to earth, allowing the wind to blow them beyond the shadow of the canopy of the parent tree. Orchids have minute seeds that can be blown away like a cloud of dust, and the wind shaking the ripe capsules of poppies scatters their tiny seeds. The seeds of dandelions and thistles usually travel just a few yards, but some fruits are dispersed over hundreds of miles by water.
Ocean currents carry the buoyant coconut across the Pacific to colonize newly formed coral atolls.
Protected by a fibrous outer coat and a hard inner shell, the coconut embryo can survive these long journeys. The seeds of alder are equipped with a corky knob, which ensures they float if they are released over water. The stream carries them until they lodge against a muddy bank where they can germinate. Animal carriers Animals can disperse plant seeds and fruits in two ways. The hooked spines of the burrs of certain plants can become caught in the animal's fur and dispersed as the animal grazers or, more commonly, the seed may be enclosed inside a tempting juicy fruit.