Clathrus Archeri

Clathrus archeri erupts from a white, egg-like sac into four to eight blood-red, tentacle-like arms coated in a slick of dark, foul-smelling slime that reeks of rotting meat — a display built entirely to summon flies.

A member of the fungal family Phallaceae, within the order Phallales, the species was first described in 1859 from a Tasmanian specimen and only received its current name, Clathrus archeri, in 1980. Its native range is debated, with Australia, New Zealand, and Africa cited as likely origins, but the fungus has since spread to Europe, North America, South America, and Madagascar.

Few fungi manage to look as unsettling and behave as cleverly at the same time. The transformation from a plain white egg into a spidery, stinking structure in a matter of hours makes this one of the more startling encounters a walk through mulch or forest litter can offer.

The clearest way to recognize Clathrus archeri is its two-stage life above ground: a white, spherical to egg-shaped structure 3 to 4 centimeters tall that splits open to release 4 to 8 pinkish-red arms, each reaching up to 10 centimeters in length. Threadlike mycelium anchors the egg at its base before rupture.

Once expanded, the upper surface of each arm is coated in a dark greenish-brown, spore-bearing gleba that dries to black with age. The whole structure lasts only a day or two before collapsing. Spores are elliptical, smooth, and measure 3.5 to 6 by 1.5 to 2 micrometers.

Aseroe rubra is sometimes mistaken for this species, but C. archeri is generally larger, its gleba runs along the length of the arms rather than being confined to the center, and its arms are thicker and typically unfused, though their tips may fuse briefly before maturity.

In laboratory cultivation on compost agar at 26 °C and pH 6.0, the thallus grew radially at up to 2.9 millimeters per day over four weeks, producing white mycelium that later turned pink; calcium oxalate crystals secreted on the hyphae are thought to form a protective, water-repelling layer. The young eggs have reportedly been eaten, described by one taster as having a slippery texture and a lingering aftertaste, though another account notes the smell and taste are generally unpleasant.

The native range of Clathrus archeri is unsettled. Some researchers list Africa, Australia, and New Zealand as its origin, while New Zealand mycologist Jerry Cooper has argued that neither Australia nor New Zealand may represent its true indigenous range, noting the fungus was considered uncommon in both countries as late as the 1930s.

The species has since spread well beyond the Southern Hemisphere and is regarded as a potential invasive species under the IUCN's definition. It was first recorded in Europe in 1914, in Britain and France, likely arriving via Australian wool imports or World War I supply chains. From France it spread to Belgium and later to Austria, Germany, Switzerland, and Italy, with further records from Bosnia and Herzegovina, Czechia, Croatia, Poland, Slovenia, Romania, and Ukraine. It has also turned up in South America and Madagascar.

The fungus favors acidic, humid soils and avoids calcareous ground. It fruits on mulch, forest litter, and woody debris, including that of Eucalyptus and Nothofagus trees in Australia and New Zealand, and has become a familiar sight in urban gardens and parks, likely spread through transported wood chips.

Recorded observations rise through the year and peak sharply around October, with a count of 4,134 that month compared to fewer than 300 in January and February. This pattern likely reflects the species' known autumn fruiting season rather than any measure of its actual population, since presence records are not a count of abundance.

As a saprotroph, Clathrus archeri breaks down dead organic matter, drawing on a range of substrates from garden mulch to woody debris such as fallen Eucalyptus and Nothofagus wood, while consistently avoiding calcareous soils in favor of acidic, humid ground.

Spore dispersal depends entirely on insects drawn by the smell of rotting meat. Flies from the families Calliphoridae, Muscidae, and Sarcophagidae land on the arms to feed on the dark gleba, then carry spores away and excrete them elsewhere, where they can germinate.

This reliance on carrion-seeking insects rather than wind places C. archeri among the fungi that have converged on a strategy more commonly associated with certain foul-smelling flowers, turning decomposition into an active partnership with the insects that also feed on decaying flesh.

Documented human use of Clathrus archeri is limited. There is no solid evidence that it has served ritual or ceremonial purposes in any culture.

Its fetid smell places it among mushrooms that folklore has generally treated with suspicion, more often avoided or regarded as an omen of decay than put to practical use, a reputation that fits the fungus's eerie, corpse-like appearance and odor.

1. The genus name Clathrus comes from the Latin word for a lattice or cage, referring to the openwork arrangement of arms seen across the genus.
2. The species epithet archeri honors William Archer (1820–1874), a Tasmanian naturalist and architect who collected the type specimen in Tasmania in the mid-19th century.
3. In the United Kingdom and much of Europe, the fungus is widely known as "devil's fingers," a name inspired by its resemblance to demonic claws pushing up from the ground.
4. The species was originally described in 1859, but did not receive its current scientific name, Clathrus archeri, until 1980, over a century later.