Henrica

Henrica is a genus of crustose lichens in the family Verrucariaceae. It has four species. These lichens grow as crusts that adhere tightly to limestone, sandstone, and other hard rocks, ranging from paper-thin films to thick, warted layers in subdued colours of white, pale grey, or fawn. They reproduce through black to dark-brown flask-shaped fruiting bodies that contain distinctive brown spores divided into numerous cells like a brick wall, giving them a characteristic muriform appearance....read more on Wikipedia.