Bamboo Fungus Identification Guide

First Impressions

You will usually smell this fungus before you see it. Walking through a bamboo grove, a shaded garden bed or a patch of rich leaf litter in the warm months, you catch a sharp, cloying, carrion-like odour drifting on the humid air, and following it you find a tall white column standing among the stems with a cloud of flies working over its tip. Then the detail that makes the species unmistakable resolves: hanging from beneath the cap is a wide, lacy, net-like veil that flares outward and downward like a crinoline skirt, sometimes reaching almost to the ground.

Nothing else in the fungal world does quite this. Once the skirt is out, identification is essentially finished and the rest of the examination is confirmation. The important thing is to look at it early in the day, because the whole structure is short-lived: it expands from the egg in a couple of hours before dawn or in the morning, stands for part of a day, and by evening it has often collapsed into a slumped, sour-smelling wreck.

The Egg Stage

Look around the base for immature specimens, because the egg tells you as much as the mature fruiting body. Eggs are white to off-white or faintly pinkish, roughly the size and shape of a hen egg or a little smaller, sitting half-buried in soil or litter, with one or more tough white cords of mycelium running from the bottom into the substrate. Press one gently: it feels firm and slightly rubbery.

Slice an egg from top to bottom with a sharp blade. The cut face is a cross-section of the whole future mushroom in miniature. Under the outer skin is a thick layer of clear gel; inside that, a dark olive-brown band which is the immature spore mass; and folded within, a compressed white column and the tightly packed pleats of the future net. That layered, jellied cross-section confirms you are looking at a stinkhorn rather than a puffball, which would show a uniform white or powdery interior with no gel and no differentiated column.

The Stipe

The mature stalk is 10 to 25 centimetres tall and 1.5 to 3 centimetres thick, white, hollow, and built from a spongy chambered tissue that in cross-section looks like a fine honeycomb or a piece of polystyrene. It tapers slightly upward and is fragile — a stalk this size holds itself up only because of the geometry of that chambered wall, and it will crush between finger and thumb with almost no resistance. At the base the stalk sits inside the ruptured remains of the egg, which persist as a soft, sac-like white to pale brownish volva.

The Cap and Spore Mass

The cap is thimble- or bell-shaped, 2.5 to 4 centimetres tall, and hangs like a cap on a peg from the top of the stalk, attached only around the apex. Its surface is strongly and irregularly pitted and ridged, resembling a network of raised chambers, and it is smeared with a dark olive-brown to almost blackish slime — the gleba, which carries the spores. At the very top of the cap is a small white ring or disc with a central perforation.

If flies have been busy, the slime may already be partly stripped, and the pale white pitted surface underneath shows through. That reticulate cap sculpture is a genuinely diagnostic character in the group and worth photographing.

The Indusium

The skirt, or indusium, is the star feature. It emerges from beneath the cap margin and hangs as a delicate white lattice with polygonal meshes, widening as it descends. In well-grown specimens it flares to a bell 8 to 15 centimetres wide and drops most of the length of the stalk. The mesh openings are large enough to see through easily. It is white in the typical form, and the whole thing is fragile enough that rain or a careless hand will tear it.

Note how far the skirt extends and how open the mesh is, because these are the characters that separate this species from its nearest relatives.

Spores and Why There Is No Print

Do not try to take a spore print. Members of this group do not release spores from a dry hymenium into still air; instead the spores are suspended in the sticky, strongly scented gleba, which insects — mostly blowflies, carrion flies and beetles — walk through and carry away on their feet and mouthparts. That is the whole ecological strategy of the group: the odour is an advertisement, the slime is the delivery vehicle, and the flies are the dispersal agents. If you want to see the spores, smear a trace of gleba on a slide; they are tiny, smooth, elliptical and pale under the microscope.

Habitat and Season

This is a fungus of warm, humid places. It is a litter and wood saprotroph that thrives in bamboo groves, where it decomposes fallen culms, leaf sheaths and the rich humus beneath, and it is equally happy in tropical and subtropical gardens, on mulch and wood chips, in plantations, and along shaded forest edges on rich soil. Fruiting follows heavy rain during the warm season and is often gregarious, with several eggs coming up in a loose group along a buried mycelial cord.

Telling It From Its Relatives

Phallus impudicus and the common stinkhorns. Same general architecture — egg, hollow spongy white stalk, slimed cap — but no skirt at all. If there is no netted veil, this is not the species.

Phallus duplicatus. Has a net, but a short one: the skirt hangs only a short distance below the cap, forming a narrow collar rather than a wide crinoline, and the mesh is finer.

Coloured netted stinkhorns such as Phallus multicolor. Built to the same plan but with a yellow, orange or pink stalk and skirt. Colour alone separates them.

Mutinus species. Slender, tapered, pointed at the tip, often flushed orange or pink, with the gleba smeared directly onto the upper stalk. No distinct cap and no veil.

Basket and lattice fungi (Ileodictyon, Clathrus). Emerge from a similar egg but expand into a hollow cage or lattice of fused arms rather than a stalk with a cap.

Morels. Occasionally confused from a photograph because of the pitted cap. In the field there is no comparison: a morel has a dry, firm, hollow cap fused to the stalk along its lower edge, no volva, no slime, no skirt and no odour.

Field Checklist

Warm season after rain; bamboo, mulch or rich litter; white egg with a rooting cord and a gelatinous layered interior; tall white hollow spongy stalk; thimble cap with a raised network and olive-brown slime; wide white lace skirt hanging beneath; strong carrion odour and attendant flies.