Monday, August 3, 2009

3 o'clock Closing Time


This scarlet pimpernel Anagallis arvensis plant was growing on the edge of some fields on the seashore at Low Newton in Northumberland. You can use this plant as a rough-and-ready clock because its flowers, which exhibit natural rhythmic sleep movements, always close up at around 3pm. in the afternoon (I took this photo at about 1pm.). It isn’t a very reliable time-piece though, as the flowers also tend to close if the sun clouds over and it begins to rain, so it’s a fair-weather clock. Quite a few plants have these natural flower closure mechanisms at different times of day – most notably Jack-go-to-bed-at-noon Tragopogon pratensis.In 1822 John Claudius Loudon, in his Encyclopedia of Gardening, listed 25 plant species with different flower closure times and suggested that they could be planted as a floral sun dial - which would be colourful but erratic.

8 comments:

  1. Well, I never knew that.
    And what an amazing sundial all those flowers would make.

    ReplyDelete
  2. Hi Phil,
    I've noticed the Yellow-wort Blackstonia perfoliata behaving similarly on Bembridge Down, closing up flowers around late-afternoon.

    ReplyDelete
  3. Nice one, Phil. I never knew that about Scarlet Pimpernel. Thanks for sharing it.

    ReplyDelete
  4. Whatever the time, its a great macro shot Phil.

    ReplyDelete
  5. Hi Keith, I don't know whether anyone has ever followed up on Loudon's planting plan and produced a living sundial.

    ReplyDelete
  6. That's intersting about the Blackstomia Rob....I was photographing it on the Durham coast one morning a few days ago, when all the flowers were open.

    ReplyDelete
  7. Thanks Roy, all down to the remarkable close-focussing (1 cm) and depth of focus of a point-and-shoot Pentax W20 pocket camera..

    ReplyDelete
  8. Hi Dean, the plant has fascinating seed capsules too, spherical with a line of weaknes around the circumference so they come apartas two hemispheres, like those old school geography map globes

    ReplyDelete