Southern strap lichen (Ramalina stenospora) on a ...

The above image is composed of two photos side-by-side, one at the top and one below it. The photo on the top shows a lichen called Southern strap lichen (Ramalina stenospora) growing on an elm twig. The lichen appears greenish with some brown spots. It's illuminated by natural light.

The bottom photo is of the same lichen but under different lighting conditions. Instead of being illuminated by daylight, it is lit up by a 365 nm ultraviolet (UV-A) blacklight. When viewed under UV light, the lichen glows red and blue in places. The background of both photos is dark.

The image shows that some organisms can fluoresce when exposed to ultraviolet radiation, which can be used for identification purposes as well as other scientific applications. – AI vision