How Does Cocklebur Spread Its Seeds? A Detailed Explanation of Its Dispersal Methods

At the mention of cocklebur, many people are surely familiar with it; it easily sticks to your body, especially to clothes like sweaters, and the whole garment can end up covered with it. So what is the method by which cocklebur spreads its seeds?

1. What is the method by which cocklebur spreads its seeds?

Cocklebur relies on animals to spread its seeds. This is because the surface of cocklebur seeds has many hooked spines that easily catch onto animals. Generally, once the cocklebur seeds mature, they drop off easily; when they come into contact with people or animals, the hooked spines catch onto their bodies and carry the seeds elsewhere to be dispersed.

2. What methods do plants use to spread their seeds?

1. Wind dispersal: Plants that spread their seeds by wind include dandelion, poplar, willow, elm and maple, among others. For example, the common dandelion and willow rely on the wind to carry their seeds far away.

2. Animal dispersal: Plants that spread their seeds by animals include persimmon, Achyranthes, bush clover, cocklebur and beggar-ticks, among others. After fruits such as grapes and persimmons are eaten by birds or beasts, the seeds are excreted along with the droppings, which serves to disperse them. Some plants have fruits or seeds that, as soon as they are touched, firmly attach to the fur of animals or the clothing of people and are carried far away, such as cocklebur and beggar-ticks. Small birds can help spread seeds; when a bird swallows a seed and it is later excreted in bird droppings, the seed can be dispersed to a new place.

3. Mechanical dispersal: Plants that spread their seeds mechanically include garden balsam, pea and sesame, among others. The fruit of garden balsam bursts open and flings the seeds in all directions, and many leguminous plants also spread their seeds mechanically.

4. Water dispersal: Plants that spread their seeds by flowing water include coconut, lotus, among others. After a coconut matures, the coconut fruit falls into the sea and drifts far away with the seawater. After the fruit of the water lily matures, it sinks to the bottom of the water; once the fruit skin rots, the seeds wrapped in a spongy outer seed coat float up and drift to other places.