Skeleton flower turns transparent when wet

The Diphylleia grayi, commonly known as the skeleton flower, exhibits a unique phenomenon where its white petals become transparent when wet. Found in the mountainous, shaded forests of Japan and parts of East Asia, including China, the plant undergoes this visual transformation within minutes of contact with rain.

The change is caused by the way water affects light dispersion. When the petals are dry, small air spaces between the cells scatter light, creating a white appearance. When rain falls, water fills these spaces, reducing light scattering and allowing light to pass through the petals more easily due to the similar optical properties of water and plant tissue. This transparency reveals the petal veins, giving the flower its skeleton-like appearance.

Once the water evaporates, air returns to the cellular spaces and the petals regain their white color. Scientists at Nanyang Technological University in Singapore are studying these optical properties to understand how water modifies material appearance, which may assist in developing substances that change transparency upon contact with water.