Codariocalyx motorius (though often placed in Desmodium), known as the telegraph plant or semaphore plant, is a tropical Asian shrub, one of a few plants capable of rapid movement; others include Mimosa pudica and the venus flytrap.
During the day and night
This plant is famous for its movement of small, lateral leaflets at speeds rapid enough to be perceivable with the naked eye. This is a strategy to maximise light by tracking the sun. Each leaf is equipped with a hinge that permits it to be moved to receive more sunlight, but the weight of these leaves means the plant must expend a lot of energy in moving it. To optimise its movement, each large leaf has two small leaflets at its base. These move constantly along an elliptical path, sampling the intensity of sunlight, and directing the large leaf to the area of most intensity.