Bamboo Fungus

Phallus indusiatus is the most theatrical of the stinkhorns. From a partly buried white 'egg' the fungus pushes up a hollow, spongy white stalk 10–25 cm tall in a matter of hours, topped by a conical, deeply pitted and ridged head coated in olive-brown slime. Beneath the head unfurls the feature that names it in several languages: a delicate white lace net, the indusium, which drops like a crinoline skirt sometimes all the way to the ground.

Stinkhorns of the Phallaceae do not shed spores into the wind. Their spores are suspended in the gleba, the dark slime that covers the head, and its powerful odour brings flies and beetles that carry the slime away on their bodies.

The whole spectacle is brief — a fruiting body typically expands at dawn, spreads its net within an hour or two, is stripped of slime by insects during the day, and collapses by evening — which makes finding a fully veiled specimen a matter of timing.

Egg stage

The immature fungus is a whitish to pale pinkish egg 3–6 cm across, half-buried in litter and attached below by a thick white cord of mycelium (a rhizomorph). Cut vertically, the egg shows a gelatinous layer, the folded olive gleba, and the compressed stalk and net waiting inside.

Head (receptacle)

The head is thimble- to bell-shaped, 2–5 cm tall, with a surface of raised ridges enclosing deep polygonal pits — a coarse honeycomb or netted texture. It is covered in olive-brown to dark greenish slime, beneath which the ridge network is pale. At the very apex is a small white perforated disc.

Skirt (indusium)

A white, finely lacy net hangs from the base of the head. The mesh is open and regular, and the skirt may extend from a few centimetres to the full length of the stalk, spreading to a bell shape in still, humid air. This structure is the single most distinctive feature of the species.

Stalk and flesh

The stalk is 10–25 cm tall and 2–4 cm thick, white, hollow, cylindrical and made of a brittle spongy chambered tissue that crushes easily. The base sits in the ruptured egg, leaving a persistent whitish to pinkish volva. There is no true spore print — the spores travel in the slime — and the flesh has no colour change on cutting, though the gleba's odour is strong and carrion-like.

The species grows in warm, damp, humus-rich ground, characteristically in bamboo groves where thick litter and decaying culms accumulate, and also in tropical and subtropical forests, plantations, gardens, roadside verges and mulched beds. It appears singly or in small scattered groups, often along the lines of buried decaying roots and stems, and the eggs are frequently found by feel among leaf litter before anything has emerged.

Fruiting follows heavy rain in the warm season and is concentrated in early morning. The distribution is pantropical: southern and eastern Asia, Australia, Africa, and Central and South America, with occasional records from warm parts of North America. It is grown commercially in China on bamboo and hardwood-based substrate, where the eggs appear in flushes on shaded beds.

Phallus indusiatus is a saprotroph that decomposes woody plant litter — bamboo culms and rhizomes, leaf litter, root fragments and buried wood. Its mycelium forms conspicuous white cords running through the litter layer, and these rhizomorphs feed the rapid expansion of the egg: nearly all of the material for a 25 cm stalk is already present, and the fungus erects it by pumping water into pre-formed spongy chambers rather than by growing new tissue.

Spore dispersal is entirely animal-mediated. The gleba emits volatile compounds resembling decay, drawing blowflies, carrion beetles and stingless bees within minutes of the head emerging. Insects visiting the slime pick up spores on their legs and mouthparts and deposit them elsewhere in the litter. Once the gleba has been removed the exposed netted head is clean and pale, which is why weathered specimens look so different from fresh ones.

Phallus impudicus, the Common Stinkhorn of temperate woodland, shares the white spongy stalk, pitted olive-slimed head and volva but has no indusium at all — no skirt hangs beneath the cap. Phallus duplicatus does produce a net, but a short one that reaches only a few centimetres below the head rather than sweeping toward the ground.

Phallus multicolor and related tropical species have brightly coloured orange to yellow stalks and skirts instead of pure white, while Mutinus species are slender, tapering, orange-to-pink columns with the gleba smeared directly on the tip and neither a distinct pitted head nor a net. Clathrus species emerge from a similar egg but expand into a hollow latticed ball or a set of arms rather than a stalk-and-cap. Skirt presence, skirt length and colour separate them reliably.