How Do Flowers Spread Their Seeds? A Full Breakdown of the Common Ways

There are quite a few ways that flowers spread their seeds. Certain activities of humans and animals can help flowers spread their seeds; natural factors such as water currents and wind can help some flowers spread their seeds; and some plants rely on their own special mechanisms to spread their seeds.

1. Self-dispersal

So-called self-dispersal means spreading by the plant body itself, without relying on any other dispersal agent. Fruits or seeds have weight of their own, and once ripe, the fruit or seed simply falls to the ground under the force of gravity, as with the velvety persimmon (Diospyros blancoi) and the big-leafed sapote (Palaquium formosanum). Some capsules and siliques, when the ripe fruit splits open, produce an explosive force that flings the seeds outward, as with the Taiwanese Michelia (Michelia compressa). Self-dispersed seeds travel only a limited distance, but some self-dispersed seeds undergo a secondary dispersal after they land on the ground; birds, ants and mammals are all possible secondary dispersers.

2. Wind dispersal

Some seeds grow appendages shaped like wings or feathers and ride the wind. Seeds with feathery appendages mostly belong to herbaceous plants, such as the hawkweed (Youngia japonica) in the aster family, while woody plants include the willow and the kapok. Some tiny seeds have a relatively large surface area compared with their weight, so they can drift on the wind, such as orchid seeds. In the aster family, the achenes of the dandelion open their pappus when ripe, like a parachute, drifting with the wind and scattering the seeds far away.

3. Water dispersal

Seeds dispersed by water have a waxy surface that does not absorb water (such as the water lily), or fruit skins containing air chambers, and a specific gravity lower than water, so they can float on the surface and be carried by streams or ocean currents. The seed coats of such seeds often have abundant fibrous tissue that keeps the seed from rotting or sinking after soaking and absorbing water. Seashore plants such as the box fruit (Barringtonia asiatica), the sea trumpet (Hernandia nymphaeifolia) and the Indian almond (Terminalia catappa) have typical water-dispersed seeds.

Once the fruits and seeds of plants are ripe, they generally rely on wind, water currents and animals for dispersal. Seeds or fruits dispersed by wind are all very light and neat in structure. For example, the round wings around the fruit of the elm and the double wings of the maple are both fairly well adapted to wind dispersal.

4. Animal dispersal

1. Birds: Most seeds dispersed by birds come from fleshy fruits, such as berries, drupes and syconia. Birds peck at the seeds of plants in the laurel family and then spit the seeds out. After the fruit is eaten, the seeds pass through the digestive tract and are excreted at random. Plants whose seeds are dispersed by birds are a relatively advanced group, because the distance over which birds disperse seeds is the greatest of all the methods.

2. Insect dispersal: pollen is used to attract insects to feed on it, thereby achieving dispersal.

3. Mammal dispersal: Dispersal by mammals mostly involves medium to large fleshy fruits or dry fruits. Generally speaking, mammals are relatively large in size and need a large amount of food, so they choose fairly large fruits. For example, the macaque likes to eat the fruits of the velvety persimmon and the banana, and thereby also helps these plants disperse.