Devils Cigar

Overview

The Devil’s Cigar (Chorioactis geaster), celebrated across international mycology as one of the rarest, strangest, and most biogeographically baffling fungi on planet Earth, is an extraordinary ascomycete fungus belonging to the monotypic family Chorioactidaceae. Commonly known in North America as the Texas Star and designated the official state fungus of Texas, this mysterious organism displays one of the most enigmatic disjunct distributions in biology, found exclusively in a few counties of north-central Texas and across isolated montane valleys in Japan—locations separated by 11,000 kilometers of ocean with identical 36th parallel latitudes.

Operating as a specialized saprotrophic wood decomposer within temperate hardwood river bottoms, Chorioactis geaster quietly recycles nutrients from the decaying roots and stumps of dead cedar elms (Ulmus crassifolia). Famous for its bizarre, explosive emergence, the fungus begins development as an unassuming, dark brown, cigar-shaped tube pushing up through the autumn leaf litter; upon reaching full maturity, the cigar violently splits open into a gleaming, multi-rayed star, releasing its spores with an audible hissing sound and a dramatic puff of smoke-like spore vapor. Secure within its highly specialized localized pockets, it is evaluated as Least Concern on the IUCN Red List.

Biology and Physical Characteristics

The anatomical engineering and spore discharge mechanics of Chorioactis geaster represent a triumph of biomechanical turgor pressure: in its immature state, the fruiting body (apothecium) is a hollow, club-shaped, dark brown to blackish cylinder covered in a dense, velvety layer of soft brown hairs (tomentum) that closely resembles a premium rolled tobacco cigar. Internally, the hollow core is lined with a smooth, gleaming, creamy-tan to saffron-orange fertile hymenial layer containing millions of microscopic, cylindrical asci packed with eight smooth, elongated ascospores. As moisture and humidity peak following cold autumn and winter rains, the internal tissues absorb water until osmotic turgor pressure exceeds the structural tensile strength of the outer wall; with explosive suddenness, the cigar ruptures along four to seven vertical seams, splitting and peeling backwards into a leathery star-shaped receptacle resembling a wooden blossom.

Behavior and Ecology

The emergence of the Texas star is synchronized with late autumn and winter rains between October and February in Texas (and spring in Japan). The moment of dehiscence is accompanied by a phenomenon almost unique in the fungal kingdom: as the pressurized seams split open, the sudden release of internal tension produces an audible, distinct hissing or snapping sound, followed by the violent, simultaneous discharge of thousands of pressurized asci. This explosive puff ejects a thick, visible, smoke-like cloud of white spores several inches into the air, allowing ambient forest drafts to disperse the spores across the forest floor. The subterranean mycelium is an obligate saprotroph that grows invisibly for years inside the subterranean root systems of dead hardwood stumps before producing its dramatic seasonal fruiting bodies.

Conservation and Human Impact

Chorioactis geaster is classified as Least Concern on the IUCN Red List due to its stable, resilient local populations across multiple counties in Texas and protected forest reserves in Japan. Because of its extremely narrow ecological association with decaying cedar elms in Texas and deciduous oaks in Japan, clear-cut deforestation, urban sprawl across the Dallas-Fort Worth metroplex, and riverbed development represent localized pressures. In 2021, the Texas Legislature officially designated Chorioactis geaster as the official state fungus of Texas, sparking widespread public interest, landholder stewardship, and protected park monitoring.

Interesting Factoid

The devil’s cigar starts as a dark brown tube that looks like a tobacco cigar, and when it’s ready to release its spores, it violently explodes open into a bright orange star with an audible hiss, blowing out a cloud of white smoke like a miniature steam engine.