Desmodium motorium - Telegraph Plant seeds

Desmodium motorium, the dancing plant, also known as Codariocalyx motorium, will delight enthusiasts of rare and unusual plants. This tropical cousin of peas is best known for the ability of its small leaflets to move laterally at a speed sufficient to be perceptible to the naked eye in response to various sound or light stimuli. This rare phenomenon is also seen, to a lesser extent, in the sensitive plant, a better-known plant from the fabaceae family. Its modest flowering occurs from late summer to autumn, in the form of clusters of small pink-violet flowers. Sow or cultivate this rare and delicate plant in a large pot indoors, and give it the gentle and humid atmosphere of its origins. It can spend summer on the terrace.

Sometimes called the 'semaphore plant', or even the 'telegraph plant', Desmodium motorium is a plant from the large fabaceae family, classified by some botanists in the genus Desmodium or Codariocalyx. This surprising species is native to tropical regions of Southeast Asia, from Bangladesh to Vietnam, including China, Malaysia, and Pakistan.

In these hot and humid countries, this herbaceous plant with simple, straight stems can reach several metres high but when cultivated in here in pots, it will not exceed 50 cm (20in) in all directions, on average. Its evergreen foliage is composed of opposing leaves, light green when young and becoming dark green over time. Each leaf is divided into three leaflets: a main leaflet, 5 to 7 cm (2 to 3in) long, located at the end, accompanied by two smaller ones at the base. These leaflets are narrow and oblong, slightly hairy on their lower surface and marked with visible veins. The small, dark pink flowers appear from August to October, gathered in panicles. The flowers are followed by elongated, hairy pods containing several seeds.

Desmodium motorium is also a medicinal plant, renowned in its country of origin for its circulatory properties, among others.

About the strange mechanism of the dancing plant:

Each large leaflet can orient itself to receive maximum light, through swelling specific cells located at their attachment to the petiole. This mechanism is also found in the sunflower.

The singularity of the Desmodium gyrans lies in the fact that it is the two small leaflets located towards the base of the petiole, in perpetual motion, that 'indicate' to the large leaflet how it should orient itself. These leaflets move fast enough for their movement to be perceptible, from bottom to top and then in reverse, following an elliptical trajectory, allowing them to constantly evaluate the brightness. This movement accelerates in hot weather and under intense light.

It was discovered relatively recently that these movements can also be triggered by certain sounds, which earned this plant the nickname of 'dancing plant'.