Magpie Inkcap

The Magpie Inkcap is the most striking of the European inkcaps, named for the bold black-and-white pattern that recalls a magpie's plumage. Like the Common Inkcap it belongs to Coprinopsis in the family Psathyrellaceae, a group of soft-fleshed, dark-spored fungi with tightly packed gills that digest themselves as they mature.

The patterning comes from the universal veil, a soft white membrane that encloses the immature fruiting body. As the cap expands, this veil cannot stretch with it and instead tears into large irregular felty patches that remain stuck to the very dark cap surface beneath. Rain gradually washes them off, so an old specimen can be almost uniformly black-brown, while a freshly emerged one is spectacularly pied.

It is a much larger and more solitary fungus than most inkcaps, sometimes reaching 30 cm in height, and it is closely tied to a particular habitat: deep leaf litter under beech on chalk or limestone. That combination of size, colour pattern and habitat makes it one of the more readily named fungi in European woodland, though its fruiting bodies are short-lived and easily missed.

Cap

5-10 cm tall and up to 8 cm wide when open, beginning as a tall white-felted egg, then elongating into a cylinder and finally opening as a bell or cone with an upturned splitting rim. The ground colour is very dark, blackish-brown to sooty grey-brown, and is overlaid with large, irregular, pure white to cream felty patches derived from the universal veil. Radial grooves run up the sides between the patches. Older caps lose the patches to rain and darken overall.

Gills

Crowded, narrow and free from the stem, white when very young but quickly turning grey and then black. As with other inkcaps they deliquesce from the margin inward, so the rim of an ageing cap drips black ink while gills near the apex are still grey.

Stipe

Tall and slender in proportion, 10-30 cm high and 0.7-1.5 cm thick, white, hollow, and covered when young in soft white woolly fibrils that wear away toward the top. The base is often slightly swollen and rooting into the litter. There is no ring.

Flesh & spore print

Flesh is thin, white and fragile. Fresh specimens carry a distinctive, unpleasant odour often likened to coal tar or naphthalene. The spore print is black, from smooth dark spores with a germ pore, and mature spores are notably large for the genus.

This species is strongly associated with beech woodland on chalk and limestone, where it fruits in deep accumulated leaf litter and on the humus-rich soil beneath. It also appears occasionally under other broadleaved trees on calcareous ground, and along the litter-filled edges of woodland rides and banks. Unlike most inkcaps it is usually solitary or in twos and threes, rather than in tufts.

Fruiting is concentrated in autumn, typically from early September through November in temperate Europe, following periods of steady rain. The species is widespread but nowhere abundant across Europe, being most frequent in the beech regions of Britain, France, Germany and central Europe, with scattered records eastward into Asia. It is largely absent from acid sandy soils.

The Magpie Inkcap is a litter-decomposing saprotroph. Its mycelium runs through fallen beech leaves and the partially decayed humus layer beneath, breaking down leaf tissue and contributing to the slow conversion of litter into soil organic matter. Because beech litter is dense, slow to decay and forms deep mats, fungi able to colonise it play an outsized role in nutrient cycling in beech woodland.

Its life cycle is compressed and dramatic. A fruiting body can emerge, elongate, expand and dissolve entirely within about twenty-four hours, which limits spore release to a short window but also limits the time available for insects and grazers to consume it. Autodigestion of the crowded gills releases spores in successive bands and carries them off in ink that drips onto the litter below and is spread further by rain splash and by flies attracted to the dissolving tissue.

Coprinopsis atramentaria, the Common Inkcap, is the nearest match in size but has a plain grey-brown cap with at most fine scurfy scales, never large white patches, and it grows in dense tufts from buried wood rather than singly in litter. Coprinus comatus is white overall with shaggy upturned scales and a movable ring on the stem, and it favours grassland and verges.

Coprinopsis lagopus shares the woolly white covering when young, but is much smaller and more slender, its veil forming a fine hairy coat rather than discrete patches, and its cap greys and rolls back rather than showing a black-and-white pattern. Larger Coprinopsis species such as C. nivea are chalk-white and powdery all over rather than dark beneath. The combination of great height, sooty ground colour, large white felty patches and solitary growth in beech litter separates the Magpie Inkcap from all of them.