This leaf is from Nelumbo nucifera, also known as lotus.
Lotus grow in slow- moving ponds or rivers, rooted in the bottom while the leaves float on the surface.
This plant has developed several unique adaptations to help it survive this environment. One such feature is that the topsides of the leaves are ultra-hydrophobic, meaning they are extremely difficult to get wet.
This is due to the nanoscale structure of its surface, which features tiny bumps that water droplets sit atop (see inset). In fact, only 2–3% of a water droplet is in contact with the leaf at any time.
This is called the lotus effect and it helps protect the plant from growth of fungi, algae, or other pathogens.
The lotus effect has been highly researched recently in order to create similar self-cleaning materials.
Try it yourself! If your leaf becomes dry or brittle, submerge it in water for a minute to regain flexibility.