Termite Mushroom

Termite Mushroom is the collective name for members of Termitomyces, a genus in the family Lyophyllaceae whose entire existence is bound to fungus-growing termites of the subfamily Macrotermitinae. Termitomyces titanicus, of the woodlands of Zambia and the Democratic Republic of Congo, is the most spectacular of them and produces some of the largest agaric caps in the world, occasionally approaching a metre across.

Every species in the genus shares a peculiar structural signature. The cap carries a hard, sharply pointed central bump called a perforatorium, which acts as a drill as the young fruitbody pushes up through baked tropical soil, and the stipe continues downward as a long, tapering pseudorhiza — a false root that connects to the termites' fungus comb deep inside their nest.

Because the mushrooms erupt in synchronised flushes after heavy rain, sometimes ringing a termite mound in a broad arc, they are among the most conspicuous seasonal fungal events in African and Asian savanna and woodland.

Cap

Broadly convex, then expanding flat with a raised centre, ranging from 10-30 cm in most species and up to remarkable sizes in T. titanicus. The colour is pale greyish brown, ochre-tan or smoky beige, darkest over the centre and paling toward the rim. The surface is smooth to radially fibrillose and often splits radially at the margin as the cap expands. At the very centre is a firm, sharply conical umbo — the perforatorium — usually darker than the rest of the cap.

Gills

Free from the stipe or narrowly attached, crowded, thin and broad, white to cream when young and taking on a pale pinkish or flesh tint as spores mature. Numerous short gills alternate with the full-length ones.

Stipe

Long, firm and fibrous, whitish to pale grey-brown, cylindrical above and tapering below into a solid, woody pseudorhiza that may run 15-60 cm or more into the ground. Digging carefully along the pseudorhiza leads to the sponge-like fungus comb of a termite nest, which is the single most conclusive identification feature for the genus.

Flesh & spore print

Flesh is white, thick, firm and unchanging when cut. The spore print is pale pinkish cream; spores are smooth and elliptical.

Termite Mushrooms grow directly from soil in savanna woodland, miombo, dry forest, plantations, roadside verges and village margins throughout tropical Africa and much of tropical and subtropical Asia. They are never found on wood or leaf litter as such, because their substrate lies underground in the termite comb.

Fruiting is tightly synchronised with rainfall, usually beginning after the first sustained storms of the wet season and continuing in flushes through it. Individual troops often appear in arcs or rings above the buried galleries of a single colony, and the same mound may produce mushrooms in the same place year after year for as long as the colony lives.

The relationship between Termitomyces and its termites is an obligate mutualism and one of the most highly evolved farming systems outside human agriculture. Worker termites gather plant material, pass it through their guts and build it into a sponge-like comb inside the nest, then inoculate the comb with fungal mycelium. The fungus digests lignin and cellulose that the insects cannot break down efficiently, and the termites graze on the nutrient-rich nodules it produces.

Mushrooms are formed only when the fungus escapes routine grazing — typically after rain and often when a colony is disturbed, weakened or in the process of dispersal. The pseudorhiza is the physical link between the comb and the surface, and the perforatorium allows the emerging fruitbody to punch through hard-crusted ground. New termite colonies acquire the fungus either from spores gathered by workers out collecting plant material or, in some lineages, by vertical transfer of mycelium carried by founding reproductives.

Other Termitomyces species are the nearest matches and differ in scale and cap shape: T. clypeatus has a small cap with a very acute, nipple-like umbo, T. robustus is stout with a broadly convex brown cap, and T. microcarpus is tiny, gregarious and grows in swarms with only a rudimentary pseudorhiza. All share free crowded gills and a pinkish-tinged print.

Macrolepiota and Chlorophyllum species reach similar sizes but have caps broken into coarse brown scales, a movable double ring on the stipe and no pseudorhiza. Volvariella species also have pink spore deposits but grow from a distinct sac-like volva at the stipe base. Amanita species can be excluded by their ring, volva and white spore print. The decisive test in all cases is excavation: only Termitomyces runs down into a termite comb.