Monday, September 3, 2012

Violent violets, with Seeds as Slippery as a Bar of Soap ....

Summer is over and it's time for plants to disperse their seeds. Some just release them on a feathery parachute, to drift away on the breeze. Others hook themselves into fur or feathers and let animals carry them passively. Others are enclosed in succulent fruits and pass through an animal's digestive system.

And then there are those with a violent tendency, with exploding seed pods and catapult mechanisms or, in the case of some members of the genus Viola (pansies and violets), a mechanism that's easier to demonstrate than describe. 

It works like this. Grip a wet bar of soap as tightly as you can, then watch the soap fly out from between your fingers. Much the same thing happens when a pansy disperses its seed. It's globular seed capsule splits into three boat-shaped sections that fold outwards and curl inwards at their edges, exerting ever-increasing pressure on the smooth-coated seeds that they enclose ..... until the seeds are violently shot outwards.

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