Overview
The Devil’s Cigar (Chorioactis geaster), also known as the Texas star mushroom, is one of the most enigmatic and geographically perplexing macrofungi in the world. Designated as the official state fungus of Texas in 2021, this rare ascomycete displays one of biology’s most astonishing disjunct distributions, occurring exclusively in a narrow corridor of central Texas and isolated forested mountains in Japan—two locations separated by thousands of miles of ocean at roughly the same latitude. Resembling a dark, leathery cigar when young, it bursts open in late autumn into a striking multi-pointed star while releasing an audible hissing sound and a miniature cloud of spore smoke.
Biology and Physical Characteristics
Prior to dehiscence, the fruiting body develops as an upright, dark-brown to charcoal, velvety club-like cylinder anchored to buried deadwood by a short stipe. As internal turgor pressure builds within microscopic asci, the outer peridium splits longitudinally from the apex downward into four to seven rays that peel backward, forming an elaborate star. The inner exposed surface reveals a smooth, creamy-tan to saffron-orange hymenium lined with millions of pressurized spore sacs. When the tension breaks, the sudden rupture of asci discharges thousands of spores simultaneously, producing a faint audible ‘hiss’ or pop accompanied by a visible vapor puff.
Behavior and Ecology
Chorioactis geaster functions strictly as a saprotroph, decomposing buried decaying roots and stumps of cedar elm (Ulmus crassifolia) in Texas and decaying oak species in Japan. Fruiting occurs during a narrow seasonal window between October and February, triggered by cold autumn rains and humid soil conditions along limestone river draws. Its bizarre disjunct distribution remains a classic biogeographic puzzle, believed by mycologists to be an ancient relict lineage dating back millions of years to a time when continuous temperate broadleaf forests spanned the northern Pacific Rim.
Conservation and Human Impact
Due to its highly restricted geographic occurrence and obligate association with specific host woods in undisturbed river drainages, Chorioactis geaster is vulnerable to urban suburban sprawl, clearing of cedar elm river woodlands, and wetland channelization. State and local naturalists in Texas actively document and protect known colonies within public greenbelts and nature preserves, emphasizing the retention of dead hardwood root systems to ensure mycelial continuity.
Interesting Factoid
When the devil’s cigar mushroom splits open, the sudden release of pressurized spore sacs creates an audible hissing sound and a visible puff of smoke, earning it the name ‘devil’s cigar.’
Last updated: October 2026