Most plants appear to us to remain still or at worst move very slowly as they follow the sun. Plants that move quickly are considered novelties with the best example being the Venus Flytrap, with its gaping mouth and scary looking “teeth”.
In Singapore and many other tropical places we would find a type of plant called “sleepy grass” or the less common scientific name Mimosa Pudica. The kids would always be amazed at such small miracles and would play with them for hours. Well the closing up part; they take 15 minutes or so to open back up and this exceeds a child’s attention span by 11,000 percent. I found this animated GIF file which shows the effect. Hypnotic, no?
The exact point of this “sleeping” is not fully understood, since it extracts a fairly large energy penalty on the plant. It may be done to reduce the desirability of the plant to herbivores or perhaps to dislodge voracious ants or caterpillars.
whoisfenton 