It’s hard for a plant to grow inside a cave, where there is little fresh air and no direct sunlight. But some plants do thrive inside caves, and one even makes its own light!
This plant is a moss that grows on the walls of some caves in Europe. The small, thin branches that make up the moss are tipped with tiny, lens-shaped cells. These cells act like magnifying glasses, absorbing the little light that does reach the inside of the cave and focusing it on the parts of the moss that need light to make food.
Some of the light is reflected out of the cells, giving a stunning gold-green glow to the walls and ceiling of the cave!