Trentepohlia umbrina

I thought this was a fungus, but it turns out that it is a subaerial terrestrial microalga. It gets dispersed in the air and makes its home on tree bark, especially pine. This species is an epiphyte, so it does no harm to its host. The orange color is due to the presence of beta carotene.

Habitat: Growing under the bark of a pine tree (Pinus sp.).