Botanical name: Codariocalyx motorius Family: Fabaceae (Pea family)
Synonyms: Hedysarum motorium, Desmodium gyrans, Hedysarum gyrans
Telegraph 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 sunlight by tracking the sun. Each leaf is equipped with a hinge that permits it to be moved in order to receive more sunlight, but the weight of these leaves means the plant must expend a lot of energy in moving it. To optimise movement of large leaves, 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. It is an erect shrub, 2-4 ft tall, with young branches velvety. Leaves are compound with 1-3 leaflets. Leaf stalk is 1-2.5 cm long. Lateral leaflets are 1-2 cm long, 3.5-4.5 mm broad, terminal leaflet 2.5-7 cm long, 6.5-13.0 mm broad, oblong- lanceshaped, blunt, hairless above, silky below. Stalks of the leaflets are about 3.5 mm long. Stipules are about 6.5 mm long. Flowers are borne in raceme in leaf axils and at the end of branches. Bracts are large, concealing the bud. Flower stalks is 3.5-6.5 mm long. Sepal cup is 2.5 mm long, hairless, teeth shorter than the tube. Flowers are 7.5-8.5 mm long, pink. Fruit is 3-4.4 cm long, 5-6.5 mm broad, slightly curved, splitting open. Telegraph Plant is found in the Himalayas, Ceylon, India, S.E. Asia, China, Malaysia, Australia, at altitudes of 400-2300 m. Flowering: August-September.
Identification credit: R. Vijayasankar
The flower labeled Telegraph Plant is ...