Verrucaria funckii

Verrucaria funckii is a species of crustose lichen in the family Verrucariaceae. It grows on rocks in aquatic environments. First described as a new species in 1826 and named after the German botanist Heinrich Christian Funck, it features a light grey-green to grey-brown, somewhat gelatinous thallus. Its reproductive structures are typically embedded within the body rather than projecting from it. The species is widespread throughout Europe, particularly in northern and western regions, as well as parts of Asia and North America, where it inhabits permanently or largely submerged siliceous rocks in streams, rivers, and lake shores. Unlike most lichens, it contains yellow-green algae rather than green algae as its photosynthetic partner (photobiont)....read more on Wikipedia.