mushroom of the warm north, never found again

Size
Height: 20–30 cm
Lifespan
1 years
Diet
Saprotrophic – fed on decaying leaf litter in warm, humid lowland forests of northern New Zealand. A mushroom built for the wet – tall, broad-capped, with a stem as thick as a man's wrist. Rose from forest floor in flushes, dozens of caps pushing through leaf litter, their pale gills releasing clouds of dark spores into the steamy air.
Habitat
Warm, humid lowland forests of northern New Zealand – kauri groves of Northland and subtropical valleys of the Coromandel. A mushroom built for the wet – tall, broad-capped, with a stem as thick as a man's wrist. Rose from forest floor in flushes after heavy rain, dozens of caps pushing through leaf litter, their pale gills releasing clouds of dark spores into the steamy air.
Range
Found in warm, humid lowland forests of northern New Zealand, notably from kauri forests near Waipoua River and subtropical valleys in the Bay of Islands. Described from early naturalist accounts and preserved specimens. Last reliably recorded in the 1880s.
Endemism
Endemic
Main Threats
Forest clearance was the primary threat. Also threatened by loss of deep leaf litter and changes in soil moisture. Last reliably recorded in the 1880s. A few pressed specimens remain in herbarium drawers – their caps flattened, their gills darkened, their subtropical forests turned to farmland and pine plantations.
Population
A true giant among meadow mushrooms. Estimated cap diameter 25–35 centimetres (the largest living Agaricus species reach 15–20 centimetres). Stem height 20–30 centimetres. Its flesh was thick and white, its gills dark chocolate-brown at maturity, and its ring large and pendulous. Last reliably recorded in the 1880s, gone by the 1900s.
Conservation Status
Extinct
The common field mushroom – white-capped, pink-gilled, appearing in paddocks after rain – is the mushroom of breakfast tables, of creamy soups, of childhood foraging. But there was once a mushroom that made the field mushroom look like a button. A giant, 35 centimetres across, with a stem as thick as your forearm, rising from the dark leaf litter of the subtropical forest. Its cap was white or pale cream, its gills were dark chocolate, its flesh was thick and fragrant. It appeared after heavy rain, in flushes that covered the forest floor like a field of pale moons. It was the giant subtropical mushroom, and it is gone. Size and sudden appearance made it special. A 35-centimetre mushroom is a spectacular thing – a cap the size of a dinner plate, a stem that could support a kilogram of flesh. It grew in flushes – sometimes dozens of mushrooms appearing overnight, pushing through the leaf litter like pale soldiers. The forest floor, dark and quiet, would suddenly be dotted with these giants. It decomposed the leaf litter. The giant subtropical mushroom was a saprotroph – it fed on dead organic matter, breaking down the fallen leaves, twigs, and woody debris of the forest floor. Its mycelium spread through the soil, digesting the litter, turning dead plants into nutrients for the living. It was a recycler, a cleaner, a hidden engine of the forest. Its mushrooms were the fruiting bodies – the reproductive structures. The caps opened, the gills darkened, and millions of dark brown spores were released into the air, drifting through the subtropical forest. It reproduced by spores, released from the gills beneath its cap. The spores were tiny, easily carried by the wind. When they landed on suitable ground – rich, damp, undisturbed – they germinated, sending out hyphae that colonised the soil. That strategy works when the forest is intact and the leaf litter is deep. It fails when the forest is cleared and the soil dries out. Forest clearance and habitat loss destroyed it. When Europeans arrived, they cleared the subtropical lowland forests for farming. The kauri, the pōhutukawa, the broadleaf – all were felled. The deep leaf litter that the giant mushroom depended on dried out or was burned. The soil, once cool and damp, became hot and exposed. Without its forest home, it could not survive. Its mycelium died. Its flushes stopped appearing. By the 1900s, 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 subtropical forest fell silent. The smaller mushrooms survived. Agaricus campestris still grows in paddocks and fields around the world – smaller, less spectacular, but alive. But New Zealand's giant subtropical mushroom is extinct – a ghost of the lowland forest, a pale moon that no longer rises from the dark leaf litter. We cleared its forest. Then we wondered why the rain no longer brought the ghosts.