Collemopsidium
halodytes on
limpets and barnacles 5 mm
Below the Verrucaria region on intertidal rocks you will often find
this species. The thallus is invisible, hidden within the shells
of these animals. The lichen fungal fruiting bodies are tiny
black spheres, also embedded in the shells. Here you can see the
tiny pitted locations (the tiniest pits you can see) but the black
nature of the fruiting bodies does not show well at this resolution.