The fairy inkcap mushroom, also known as trooping crumble cap, is a small white mushroom with a long, thin, hollow stem and an almost round white cap which will eventually turn gray-brown as the fungus ages. It is a “vegetarian” fungus, and typically appears in often quite large clusters around the bases of tree stumps. The Latin name is Coprinellus disseminatus.
These fragile little mushrooms have inky black gills and dark gray, bell-shaped caps at maturity. They are tiny and disintegrate when touched. Other related mushrooms (there’s a reason they’re called inkcaps) literally turn to ink — deliquesce — when touched, but these simply dissolve.