Mycoblastus sanguinarius

Mycoblastus sanguinarius, commonly known as the bloody heart lichen, is a widespread species of crustose lichen in the family Tephromelataceae. It is distinguished by its pale to dark grey thallus, which can appear very irregular and uneven, often with a thick, coarse, wart-like texture. The thallus may be continuous or somewhat cracked, with a prothallus that ranges from pale to dark grey. The apothecia (fruiting bodies) are frequent, black, and become convex or hemispherical as they mature. These structures develop on a bright carmine-red thalline cushion, which is revealed when the thallus is damaged or worn. The lichen grows in temperate and montane forests across Asia, Europe, and North America. Usually found on tree bark, it has been recorded less frequently on decorticated wood and moss-covered rocks....read more on Wikipedia.