Split Gill Fungus
Schizophyllum commune
The Split Gill Fungus (Schizophyllum commune) is a remarkably widespread and common wood-decaying fungus belonging to the family Schizophyllaceae. It is one of the most frequently encountered bracket fungi on decaying wood worldwide and is notable for its distinctive gill structure, which gives the species its common name.
• The genus name Schizophyllum derives from the Greek "schizo" (split) and "phyllon" (leaf/gill), referring to the characteristic longitudinally splitting gill-like folds on the underside of the cap
• It is considered one of the most cosmopolitan fungi on Earth, found on every continent except Antarctica
• Schizophyllum commune holds the record for having the largest known mating system of any fungus, with over 23,000 distinct mating types
• It is a model organism in mycology, widely studied for its genetics, wood-decay mechanisms, and mating-type biology
Taxonomie
• First described by the mycologist Elias Magnus Fries in 1815
• The genus Schizophyllum is small, containing only a handful of recognized species, with S. commune being by far the most common and widespread
• Fossil evidence of Schizophyllum-like fungi dates back to the Eocene (~44 million years ago), with specimens preserved in amber
• It has been documented in tropical, subtropical, and temperate regions across Asia, Africa, the Americas, Europe, and Oceania
• Its extraordinary dispersal ability is attributed to its tiny, lightweight basidiospores, which can travel vast distances on air currents
Cap (Pileus):
• Typically 1–5 cm wide, fan-shaped, semicircular, or shell-shaped
• Surface is densely covered with fine hairs, giving it a woolly or felted texture
• Color ranges from white to pale gray, grayish-brown, or tawny when fresh; often fading to whitish when dry
• Margin is typically inrolled and wavy
• Texture is tough, leathery, and flexible — can revive after drying when rehydrated
Gills (Lamellae):
• The defining feature: gill-like folds that are split or cleft longitudinally along their length (hence "split gill")
• Radially arranged, narrow, and densely packed
• Color is pale gray to pinkish-gray
• The split gills are actually not true gills but pseudogills — folds of tissue that bear the hymenium
Underside & Spore-Bearing Surface:
• The split gills bear the hymenium (spore-producing layer) on both surfaces of each fold
• Spore print is white
Stipe (Stem):
• Lacks a true stipe; fruiting bodies are laterally attached to the substrate (sessile to effused-reflexed)
Spores:
• Basidiospores are small, cylindrical to ellipsoid, smooth, and hyaline (transparent)
• Approximately 3–4 × 1–1.5 µm in size
• Produced in enormous quantities on the hymenium lining the split gills
Habitat:
• Found on dead hardwood and, less commonly, on coniferous wood
• Commonly colonizes fallen branches, logs, stumps, and cut timber
• Frequently encountered on processed wood products such as wooden fences, pallets, and construction lumber
• Can fruit year-round in tropical regions; in temperate zones, fruiting is most common in warm, humid conditions
Decay Type:
• Causes white rot — it degrades both lignin and cellulose in wood
• Produces extracellular enzymes including laccases and cellulases that break down wood polymers
• This white-rot capability makes it ecologically significant in carbon cycling in forest ecosystems
Environmental Tolerance:
• Remarkably desiccation-tolerant — fruiting bodies can dry out completely and revive upon rehydration, producing spores again
• Tolerant of a wide temperature range, though optimal growth occurs at 25–35°C
• Can colonize wood with relatively low moisture content compared to many other wood-decay fungi
Distribution:
• One of the most commonly isolated fungi from air spore samples worldwide
• Found from sea level to montane forests
• Particularly abundant in tropical and subtropical regions
• Not recommended for consumption — too small and too tough to be of culinary value
• There are rare reports of it causing human infections, particularly in immunocompromised individuals, including sinusitis and pulmonary infections
• It is one of the few basidiomycete fungi known to act as an opportunistic human pathogen
• Some tropical cultures do consume young, tender specimens, but this is uncommon
Substrate:
• Grows readily on sterilized hardwood sawdust, logs, or wood chips
• Commonly cultured on malt extract agar or potato dextrose agar in laboratory settings
Environmental Conditions:
• Optimal growth temperature: 25–35°C
• Requires moderate humidity for fruiting body development
• Tolerates a wide range of environmental conditions, including periodic drying
Cultivation Notes:
• Inoculation is typically performed using spore suspensions or mycelial plugs
• Mycelium is white, cottony, and fast-growing on agar media
• Fruiting can be induced by lowering temperature and increasing fresh air exchange
• Due to its status as an opportunistic pathogen, cultures should be handled with appropriate laboratory precautions, especially by immunocompromised individuals
Scientific Research:
• Widely used as a model organism in fungal genetics and molecular biology
• Its extraordinarily complex mating-type system (with over 23,000 mating types governed by two genetic loci, A and B) has made it a key species for studying fungal sexual compatibility and evolution
• Used in studies of wood decay mechanisms, particularly white-rot enzyme systems
Biotechnology:
• Produces laccase enzymes of interest in bioremediation, bio-pulping, and industrial biotechnology
• Studied for its potential in degrading environmental pollutants, including dyes, pesticides, and other xenobiotic compounds
• Its cellulase enzymes are of interest in biofuel production research
Traditional and Regional Uses:
• In parts of Southeast Asia and India, young specimens are occasionally consumed as food
• In some traditional medicine systems, it has been used for its purported antimicrobial properties
• In Nigeria and parts of West Africa, it is among the wild mushrooms gathered and consumed by local communities
Anecdote
Schizophyllum commune holds one of the most extraordinary records in the biological world: it has the largest known mating system of any organism, with over 23,000 distinct mating types. • Unlike most organisms that have two sexes (male/female) or a small number of mating types, S. commune's mating compatibility is governed by two unlinked genetic loci (A and B), each with multiple alleles • Any two individuals with different alleles at both the A and B loci can mate — this combinatorial system generates tens of thousands of mating types • This means that any two randomly encountered individuals have a very high probability (~98%) of being sexually compatible • The system is thought to have evolved to maximize outcrossing and genetic diversity in a species that relies on chance encounters between compatible mycelia in the wild The Split Gill's "Catapult" Spore Release: • Like many small fungi, S. commune uses a surface tension-based "ballistospore" launch mechanism • A tiny water droplet (Buller's drop) condenses on the base of each spore and merges with a thin film of water on the spore surface • The sudden shift in surface tension launches the spore away from the gill surface at accelerations exceeding 10,000 g • Despite this impressive launch, the spore quickly decelerates due to air resistance and drifts away on air currents Desiccation Superpower: • The fruiting bodies of S. commune can dry out completely for months or even years and then revive upon rehydration, producing viable spores again • This remarkable ability allows it to fruit intermittently over many years from the same piece of wood, taking advantage of brief periods of favorable moisture
En savoir plus
