Amazing Seed Adventures: How Seeds Travel

A seed has no legs, no wings, and no say in the matter. And yet seeds turn up on mountainsides, on brand new islands, and in the crack of a pavement halfway down your street. Every one of them got a lift from something.

Here are the four ways they hitch it.

Wind power

Some seeds are light and fluffy, perfect for catching the wind. These seeds can travel long distances.

• Dandelion seeds: these have a tiny parachute that helps them float.
• Maple seeds: these spin like helicopters when they fall from the tree.

Try this: find a dandelion seed head and blow on it. Watch the seeds fly away, and see how far they are still going when you lose sight of them.

Animal helpers

Animals play a big role in moving seeds around. Some seeds have hooks or barbs that stick to fur or feathers. Others are inside fruits that animals eat.

• Burdock seeds: these have tiny hooks that cling to animal fur.
• Berries: birds eat berries, then pass out the seeds in a new location. Not glamorous, but it works.

Water ride

Seeds that grow near water often travel by floating. These seeds are usually lightweight and have a waterproof coating to protect them on the journey.

• Coconut: this giant seed can float across the ocean to new islands.
• Mangrove seeds: these float, and can even start growing roots while still in the water.

Seed-slinging plants

Some plants do not wait for a lift at all.

• Touch-me-nots, also called jewelweed, have pods that burst open when touched, flinging the seeds away from the parent plant.

Wind or water?

These four seeds all travel without any help from an animal. Two ride the wind, and two float. Sort them.

A question worth asking

All of this is called seed dispersal: a plant getting its seeds away from itself.

And it is a strange amount of trouble to go to. A parachute is not free — the plant has to build it. Neither is a hook, or a husk thick enough to survive an ocean, or a pod wound tight enough to fire. Every one of those costs the plant something it could have spent on growing instead.

So why bother? Why not simply let the seeds drop straight down, and save the effort?

Next time you are outside, look at what has stuck to your socks — those are seeds, and you are the animal.