Slender orange-bush lichen (Teloschistes exilis ...

The image depicts two photographs of a lichen on an elm twig. The top photograph shows the lichen under normal daylight conditions, with the coloration appearing to be a mixture of green and yellow hues. The bottom photograph shows the same lichen illuminated by a 365 nm ultraviolet (UV-A) blacklight.

**Image Details**

* **Photographs**
* Top: The top photograph is taken in natural daylight.
* Bottom: The bottom photograph is taken under illumination from a 365 nm UV-A blacklight.
* **Lichen Coloration**
* Under normal daylight conditions, the lichen appears green and yellow.
* When illuminated by a 365 nm UV-A blacklight, the lichen turns orange.

**Conclusion**

The image demonstrates how certain organisms can fluoresce or change color under different lighting conditions. The use of UV-A light to illuminate the lichen reveals its true colors, which are not visible in normal daylight. This phenomenon is likely due to the presence of fluorescent pigments within the lichen's cells that absorb and re-emit light at specific wavelengths. – AI vision