The Dune Brittlestem (Psathyrella ammophila) is a salt-tolerant mushroom that grows on sand dunes and is common in northern Europe. Its Greek-derived scientific name means "sand-loving" (ammophila) and "friable" or crumbly (Psathyrella), a reference to its fragile texture. It is an inedible fungus that varies in colour and shape with age and considered rare or threatened in specific regions.