The Skeleton Flower
The Skeleton Flower – Diphylleia grayi
On the cold, wet mountainsides of Asia and the Appalachians, a unique plant grows tucked away in shady grottoes on the forest floor. Its singular defining feature, however, can only be seen in Spring, when clusters of bone-white petals unfurl, revealing small, pert flowers wreathed in the few rays of dappled sunlight that managed to pierce the canopy above. But unlike most flowers, the color of the petals isn’t caused by a pigment, but instead is the result of a unique interplay of light and intercellular structure. The cells that comprise the petals are widely spaced, with several vacuous lacunae in-between. These empty spaces are filled with air, and when sunlight is refracted between this air and the cytoplasm of the cells, it imbues the petals with a white hue. However, when it rains, the petals absorb water, which fill the lacunae; now when sunlight is refracted, it’s between two liquids, that of the absorbed rainwater and the cytoplasm, both of which have similar refractive indices. This means that when light hits the petals, instead of being reflected back, it can pass straight through the liquid-liquid medium unhindered, causing the flowers to become transparent.
Yong, J., Chen, F. Yang, Q., Du, G., Shan, C., Bian, H., Farooq, U., & Hou, X. (2015). Bioinspired transparent underwater superoleophobic and anti-oil surfaces. Royal Society of Chemistry 3: 9379-9384.
Original picture retrieved from: http://www.lostateminor.com/2014/11/18/flower-turns-amazingly-transparent-touched-raindrops/