It’s name is Himawari (Japanese for sunflower) and its design has apparently been influenced by the motion pattern of sunflowers, with it reacting to human movements. The stalk is driven by servo motors and there are alloy actuators in the head, but it is the reflected light from the white LED tentacles – and infrared LEDs which are used to reflect IR light – that enables movement to be tracked.
Thanks to botropolis.com, and more info can be found on the AnderDesign website:
Himawari is an originally created robotic plant, influenced by the sunflower. Using an infrared camera in the plant as eyes, Himawari moves, following human movement. The stalk of the plant is driven by servo motors. There are two kinds of LEDs in the head of the plant. Infrared LEDs which are used to reflect IR light from the human motion into the camera, and white LEDs that shine inside the flower. Originally developed shape-memory alloy actuators are used to move the petals of the flower and the tentacles inside the head. 80 shape-memory alloy actuators and 48 white LEDs wriggle and twinkle according to human movements. This wriggling and twinkling reaction introduces the expression of Himawari.