[Karen W. (OP)]

Well some flowers burst open and spew their seeds for many feet in front of them and are carried on the wind to their resting place to start again, but how are the seeds propelled at such a distance from the flower. What is it that causes such propulsion? What is the physical strength behind it?? Do you know what I mean?

In humans I assume the contraction of muscle to propel the sea-men? LOL LOL.. sorry, but a flower seems different? Do they have some type of physical structure which allows this or is it pressure built up in the drying pod which propels them. Is it made so when too much pressure is built up, that the pod bursts???

[bryan]

This is called explosive or mechanical dispersal and is another example of plants harnessing energy from the sun. It is commonly used by legumes such as peas and beans but also by other plants. Seed pods are dried out by heat from the Sun which builds up tension in their walls. Eventually this tension splits the walls into two halves which recoil backwards like a spring firing the seeds sometimes over 10m.

[sarah cp]

I know of a plant which does this spectucularly - Himalayan Balsam. A weedy looking plant with purple flowers. When the seed pods are ripe even the smallest touch is enough for them to explode. Presumably this evolved to be triggered by passing animals or strong gusts of wind. Its fun to pick them gently then throw them at people so that they explode when they hit them!

[Bored chemist]

There are other ways of spreading seeds. If I just put the name of this one people might think I was joking so here's a wiki page.
http://en.wikipedia.org/wiki/Squirting_cucumber

[Karen W. (OP)]

There are other ways of spreading seeds. If I just put the name of this one people might think I was joking so here's a wiki page.
http://en.wikipedia.org/wiki/Squirting_cucumber

OOOOH we have those here we just used to reverse the vacuum cleaner an old friends mom had, she called it her little green pig! If she had known we were shooting those wild poison cucumbers out of the vacuum we would have been dead ducks.. LOL.. I think we may have ruined 2 of her vacuums growing up! LOL... We were able to reverse the suction and make her little pig a great blow gun for those cucumbers! LOL!!

[Karen W. (OP)]

This is called explosive or mechanical dispersal and is another example of plants harnessing energy from the sun. It is commonly used by legumes such as peas and beans but also by other plants. Seed pods are dried out by heat from the Sun which builds up tension in their walls. Eventually this tension splits the walls into two halves which recoil backwards like a spring firing the seeds sometimes over 10m.

THanks thats an interesting answer..

[Karen W. (OP)]

I know of a plant which does this spectucularly - Himalayan Balsam. A weedy looking plant with purple flowers. When the seed pods are ripe even the smallest touch is enough for them to explode. Presumably this evolved to be triggered by passing animals or strong gusts of wind. Its fun to pick them gently then throw them at people so that they explode when they hit them!

I have never seen one of those plants.. You sound like us when we were kids! LOL!

[blakestyger]

I've got a weed in my garden that does that, a bittercress - it's very persistent and seems to go on all the year round; it even flowers under the snow.
If one gets to the seed pod stage before being weeded it explodes when touched and the whole wretched business starts all over again, not LOL.