Gregorella

Gregorella is a fungal genus in the family Arctomiaceae. It is a monotypic genus, containing the single lichen species Gregorella humida. This lichen grows as a thin, ephemeral crust on damp, shaded bark or rock, appearing olive to dull grey-brown when dry but swelling slightly and turning bluish-grey after rain. It is built from tiny clusters of blue-green algae wrapped in fungal cells and reproduces through small, button-like fruiting bodies that contain eight colourless, oval ascospores lacking cross-walls. ...read more on Wikipedia.