Rock Tripe
Thallus small, flat, and wrinkled, circular in shape; brownish-gray and brittle when dry, greenish-black and rubbery when wet. Attached from a single point of the thallus to the rock. On rock in open, cold habitats. At least fifteen species of Umbilicaria occur in this region.
![Alaska species lichens Rock Tripe](https://uploads.alaska.org/guides/alaska-species-guides/alaska-lichens/_960xAUTO_fit_center-center_65_none/alaska-species-lichensRock-Tripe.jpg)