Wednesday, November 3, 2010

Sensitive Briar

Click to enlarge
I came across one of my favorite plants while hiking our glade.  The Sensitive Brier (a.k.a. Catclaw Brier) or Mimosa nuttallii is a delicate plant which is quite shy.  Its fame comes from its ability to fold up its leaflets temporarily when it is touched or sometimes when the sky turns overcast.

The pictures to the right are before and after a light touch.  The action takes place in less than a second.  Cleverly called "rapid plant movement", it is a property of several plants in the Mimosa family.  The Venus Flytrap's capture of insects is another example of rapid plant movement.  Also some plants are able to flip out pollen with their petals at half the speed of sound!
One second later
By clicking on the picture, you can appreciate the small recurved thorns on the stem.  When brushing the leaves to get them to perform, the thorns painfully remind me to go easy. In spite of these tiny thorns, cattle love to graze on the brier.
Beautiful delicate blossoms appear in early summer.  A more detailed description is at Wikipedia.  You can watch the leaves fold up in a short video of another Mimosa species.