Dancing Plant

Have you ever watched a plant move all by itself? The unusual Desmodium gyrans, also known as the ‘Dancing plant’, is another of the few plants in the world that visibly - and quickly - moves its leaves when exposed to touch, sunlight, warmth or even small vibrations - hence the reaction to music and sound. http://www.spain-info.co.uk/gardening/dance-plant.htm But I can not find where to get the seeds