Pixie's Parasol

Mycena interrupta is arguably the most photographed small fungus of the Southern Hemisphere. Its cap is a vivid sky-blue to turquoise, deepest in the centre and paler towards a finely striate margin, and the whole fruit body has a glassy, gelatinised surface that catches the light. Against the dark, sodden wood of a rainforest log, a colony can look like scattered beads of blue glass.

The species is a wood-inhabiting bonnet of cool, high-rainfall temperate forest, with a classic Gondwanan distribution: Australia — especially Tasmania and Victoria — New Zealand, New Caledonia and southern South America. It has no close blue-capped counterpart in the Northern Hemisphere, which is part of why it has become such an emblem for Australasian fungal diversity.

A structural detail sets it apart from most bonnets: the stipe does not simply insert into the wood but ends in a small, flattened, disc-like basal pad that clamps onto the substrate, a feature easily seen with a lens and useful for confirming the identification.

Cap

The cap is 5–20 mm across, hemispherical to convex, becoming shallowly bell-shaped. The surface is smooth, distinctly gelatinous or glassy, and finely translucent-striate with radial grooves from the margin. Colour is a brilliant sky-blue to turquoise or deep cyan when fresh, strongest at the centre, fading towards greyish-blue, pale bluish-white or almost colourless in old or sun-exposed specimens.

Gills

Gills are adnate to slightly decurrent by a tooth, distant, and pale blue to whitish with distinctly blue edges when fresh. As the fruit body ages the blue fades and the gills become whitish or pale grey.

Stipe

The stipe is 10–30 mm tall and less than 1 mm thick, hollow, gelatinous-glassy and pale blue, becoming more translucent with age. Its base flares abruptly into a small circular basal disc that adheres to the bark or wood surface — the character named in older literature as the attachment pad.

Flesh & spore print

The flesh is a mere film, watery bluish and gelatinised. There is no distinctive odour. The spore print is white; spores are smooth and amyloid.

Pixie's Parasol fruits on well-rotted fallen logs, branches, bark and woody litter in cool, wet temperate rainforest and tall wet eucalypt forest. It particularly favours the mossy, permanently damp surfaces of logs in gullies, under tree fern canopies and along creek lines, and is often found on myrtle beech (Nothofagus cunninghamii) and eucalypt wood in Australia.

The species is characteristic of Tasmania and southern mainland Australia, and also occurs in New Zealand, New Caledonia and southern South America, reflecting a Gondwanan distribution across cool-temperate southern forests. Fruiting is tied to the wet season, generally autumn into winter, and colonies of many fruit bodies may appear along a single log after sustained rain.

This is a wood saprotroph, decomposing the soft, water-saturated outer layers of well-rotted logs and bark in the late stages of decay. Its mycelium is confined to the surface and immediately subsurface layers of the wood, which is consistent with the tiny basal disc anchoring the fruit body directly to the substrate face.

The species requires continuously high humidity: the gelatinised tissues rapidly shrivel in dry air, so fruiting is restricted to the wettest microsites in the forest. It forms part of the rich fungal community that recycles coarse woody debris in Southern Hemisphere rainforest, a role shared with a large assemblage of small agarics, corticioid fungi and ascomycetes on the same logs.

The blue colour has few competitors in its range. Mycena cyanorhiza shows blue only at the very base of the stipe, with a pale greyish cap, and is a Northern Hemisphere species. Entoloma hochstetteri, another famous blue New Zealand fungus, is far larger, has a dry conical fibrillose cap on a stout stem, and produces a pink spore print rather than white.

Faded specimens of M. interrupta may lose almost all blue and can then resemble other small pale wood bonnets, but the gelatinous glassy texture and the flattened basal disc remain diagnostic. Small blue-tinged Mycena elsewhere in the world generally lack the disc-like attachment and the strongly gelatinised cap surface.