Monday, July 6, 2009

An Exquisite Seed Dispenser

This elegant little object is the glassy seed capsule of a common and easily overlooked wild flower: mouse-ear chickweed Cerastium fontanum. You can find an excellent photograph of the plant in bloom over at
After the flowers fade they're followed by these exquisitely formed seed containers, each about a centimetre long at maturity. This capsule has shed all of its seeds except one, which you can just make out inside the vase-shaped neck. Those teeth that surround the opening bend back to allow the seeds to be shaken out in dry weather and close up when it’s wet – a mechanism that also operates in white campion seed capsules. You can make it go through the motions by putting it in a sealed container with moist paper towel in the bottom, then bringing it out into dry air.


  1. Fascinating Phil, and so clever to open like that at the right time. I find that incredible how that has evolved how to do that.

  2. Hi Keith, it's the same mechanism that opens and closes pine cones - microscopic fibres in the dry cell walls that expand or shrink when the absorb water of dry out, that bend the whole structure.


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