About Umbilicaria deusta (L.) Baumg.
Umbilicaria deusta, commonly called peppered rock tripe, is a widely distributed species of saxicolous lichen belonging to the family Umbilicariaceae. Carl Linnaeus first formally described this species in his 1753 publication Species Plantarum, under the name Lichen polyphyllus. In 1790, German botanist Johann Christian Gottlob Baumgarten moved the species to the genus Umbilicaria, creating the currently accepted scientific name Umbilicaria deusta (L.) Baumg. This lichen produces a dark brown to nearly black thallus, which usually grows to 1 to 5 cm (0.4 to 2.0 inches) in diameter. Its upper surface is covered in tiny black dots that are actually granular isidia. The lower surface shares the same colour as the upper surface, and is either smooth or covered with small dimples. Umbilicaria deusta grows on exposed boulders and rocky outcrops.
