A Seed’s Journey
Walking through the forest, you’ll come across many different kinds of trees, flowers and shrubs. But have you ever wondered how all of these types of plants made it to there?
Plants have many ways of spreading their seeds to new places. They reproduce through a process we call seed dissemination. It is naturally achieved in four ways.
Some species of plants grow their seeds in special pods. As these pods dry out in the sun, they begin to crack at fault lines in the pod. Eventually, the pods burst and fling seeds at high speed away from the plant. Well-known varieties of seed pod plants include the common gorse native to western Europe, and the touch-me-not native to South and Central America.
Some plants have developed an ability to produce light-weight seeds that can stay airborne for a long time. These seeds can be picked up by the wind and transferred a considerable distance. The dandelion is the most common of this type of plant. The “helicopter’” seeds of maple and sycamore trees are also very widespread in North America.
Aquatic plants, coconut trees, mangrove trees and many other species of plants use waterways to spread seeds. Some plants produce lightweight seeds, stick-like seeds and seeds with waterproof coverings to keep salt water off them. These seeds can float on water or be carried by winds into the water. Eventually the seeds land on beaches, sink into the silt at the bottom of a pond or river- bed soil to germinate and grow.
Animals can often come into contact with plants that have developed seeds that can stick to fur and skin. Plants such as the common cocklebur, have evolved hooks on their seeds to attach to animals for transport. Certain types of berries, like blackberries, have evolved to have hard, indigestible seeds. When animals ingest them, they dispel the seeds whole and the seeds grow wherever they fall.
1. The touch-me-not comes from a group of plants known to respond with rapid movements to touch and other outside stimuli, including the famous Venus flytrap.
2. The tumbleweed has the most unique way of using wind to spread its seeds. When the plant begins to die, it detaches from its roots and allows the wind to blow away the dry husk of its plant, dropping seeds wherever it rolls.
3. Mary’s Bean, a seed from a morning glory plant native to southern Mexico and Central America, has been found more than 15,000 miles (24,140 km) away in Norway!
4. Many invasive species of plants, like the burdock and the Japanese stiltgrass, are spread by seeds sticking to peoples clothing or shoes.