Definition: Hadrestia is a type of plant or fungus that primarily grows on the surface of rocks, particularly in arid regions and has been found in various parts of the world. It is characterized by its small size and often resembles a tiny mushroom with a single, round, white cap. Hadrestia's growth patterns can vary widely, but they are typically monomorphic or pseudomonophytic, meaning that they do not have a defined root system.