You have never heard of this fungus. That is the point. It was tiny – so tiny that you could walk along the beach and never see it. Its cap was the size of a grain of rice, its stem was fine as a hair, its entire being was compressed into a few square millimetres of driftwood. It was the beach ghost of the shore, a living recycler on the salt-soaked wood. Its habitat made it special. The tiny coastal fungus grew only on driftwood in the upper intertidal zone – the place where the highest tides leave their debris, where the wood is soaked with salt, dried by the sun, and soaked again. It was a specialist of the edge, the boundary between the sea and the land. The cap was pale brownish-grey, bell-shaped, with a tiny fringe at the edge. The gills were white, spaced widely apart. The stem was so thin that it was almost invisible. The whole mushroom was a ghost, a whisper, a hint of a fungus on a piece of driftwood. It decomposed. The tiny coastal fungus was a saprotroph – it fed on dead organic matter, breaking down the lignin and cellulose of the driftwood, turning it back into nutrients for the coastal ecosystem. It was a recycler, a cleaner, a hidden engine of the beach. Fungi reproduce by spores, released from the gills beneath the cap. The tiny coastal fungus produced spores in tiny, white clusters. The spores were carried by the wind and the sea spray, landing on other pieces of driftwood, waiting for moisture to germinate. That strategy works when the beach is wild and the driftwood is abundant. It fails when the beach is cleaned and the wood is removed. Beach cleaning and coastal development destroyed it. When Europeans arrived, they began to clean the beaches – removing driftwood for firewood, for construction, for aesthetics. The tiny coastal fungus, which grew only on driftwood, lost its home. At the same time, coastal development destroyed the natural beaches. Seawalls, promenades, and houses replaced the wild shoreline. The driftwood that once accumulated in piles on the high tide line was cleared away. The fungus could not survive. By the 1910s, it was gone. The last specimens were probably collected by a naturalist who had no idea he was holding the final individual. He pressed them, dried them, put them in a drawer. And the beach fell silent. The larger fungi survived. They are more adaptable, able to grow on a wider range of substrates. They are the survivors, the ones that kept their heads down. But the tiny coastal fungus is extinct. A few pressed specimens in a herbarium, a few spores in a core sample, and the memory of a fungus that used to grow on the driftwood of New Zealand's wild beaches, a beach ghost on the shore. The beach ghost has faded. The shore is not as wild as it used to be.