Jelly Ear
Auricularia auricula-judae
Jelly Ear (Auricularia auricula-judae) is a species of edible fungus in the family Auriculariaceae, widely recognized by its distinctive ear-shaped, gelatinous fruiting bodies. Also known as Wood Ear, Judas's Ear, or Black Fungus, it is one of the most commonly consumed fungi in East Asian cuisine and traditional medicine.
• Belongs to the phylum Basidiomycota, a major division of fungi that produce spores on specialized cells called basidia
• The species name "auricula-judae" translates to "ear of Judas," referencing the biblical figure Judas Iscariot, who is said to have hanged himself on an elder tree (Sambucus nigra), where this fungus commonly grows
• Has been cultivated and consumed in China for over 1,000 years, making it one of the earliest cultivated fungi in human history
• Known in Chinese as 木耳 (mù ěr) and in Japanese as キクラゲ (kikurage)
• Native range spans temperate and subtropical regions across Europe, Asia, North America, and parts of Africa and Australia
• Most commonly found growing on dead or dying wood of deciduous trees, particularly elder (Sambucus nigra), but also on beech, oak, sycamore, and other broadleaf species
• The genus Auricularia comprises approximately 8–10 recognized species worldwide, with A. auricula-judae being the most widely known in temperate regions
• Closely related species such as Auricularia polytricha (Cloud Ear / Black Fungus) are more commonly cultivated and consumed in tropical and subtropical Asia
• Fossil records of Auricularia are scarce due to the soft, gelatinous nature of the fruiting bodies, which do not preserve well; however, molecular phylogenetic studies suggest the genus diverged during the Cretaceous period
Fruiting Body:
• Shape: Ear-shaped (auriculate), often resembling a human ear; typically 3–8 cm in diameter, occasionally up to 12 cm
• Texture: Gelatinous and elastic when fresh; becomes hard and brittle when dry, then rehydrates upon soaking
• Color: Upper surface is reddish-brown to dark brown, sometimes with a purplish tinge; covered with fine, minute grey hairs
• Undersurface: Smooth to slightly wrinkled, lighter brown to grey-brown, often with a faint vein-like pattern
• Consistency: Translucent when held up to light; rubbery and cartilaginous
• Typically grows singly or in overlapping clusters (imbricate) on wood
Microscopic Features:
• Basidia are cylindrical and septate (divided by cross-walls), characteristic of the Auriculariaceae family
• Spores are sausage-shaped (allantoid), measuring approximately 11–14 × 4–6 µm
• Spore print is white
• Hyphal system is monomitic (composed of generative hyphae only)
When dried, the fruiting bodies shrink dramatically and become dark, hard, and nearly black — a form in which they are commonly sold in Asian grocery stores worldwide.
• Primary ecological role: Causes white rot in dead and dying hardwood, breaking down lignin and cellulose in wood
• Commonly found on standing dead trees, fallen branches, and cut stumps
• Shows a strong preference for elder (Sambucus nigra) but colonizes a wide range of deciduous hosts
• Fruiting season in temperate regions: Primarily autumn (September–November), though fruiting bodies can appear year-round in mild conditions
• Fruiting bodies can persist on wood for extended periods in dry weather, rehydrating and releasing spores when moisture returns
• Spore dispersal: Basidiospores are released from the smooth undersurface and dispersed by wind; the fungus can also spread vegetatively through its mycelium in wood
• Plays a key role in nutrient cycling in forest ecosystems by decomposing woody debris
• Often found in woodland edges, hedgerows, parks, and gardens where elder and other host trees are present
Cultivation Substrate:
• Traditionally grown on logs of deciduous trees (especially oak, beech, and elder)
• Modern commercial cultivation uses sawdust-based substrates supplemented with wheat bran, rice bran, or cottonseed hulls
• Substrate is sterilized or pasteurized before inoculation with spawn
Environmental Conditions:
• Temperature: Mycelial growth optimal at 22–28°C; fruiting body formation triggered at 15–25°C
• Humidity: Requires high relative humidity (85–95%) for fruiting body development
• Light: Low light or diffuse light is sufficient; direct sunlight should be avoided
• Air circulation: Good ventilation is essential to prevent CO₂ buildup, which can cause abnormal fruiting body development
• pH: Slightly acidic conditions (pH 5.0–6.5) are optimal
Growth Cycle:
• Spawn run (mycelial colonization): 3–5 weeks depending on temperature and substrate
• Fruiting body development: 5–7 days from pinhead to mature fruiting body
• Multiple flushes can be harvested from a single substrate block over several weeks
Harvesting:
• Harvest when fruiting bodies are fully expanded but before they become overly tough
• Fresh fruiting bodies should be dried promptly for long-term storage; dried product rehydrates well in water
• China produces the majority of the world's supply, with annual production exceeding 7 million metric tons (including all Auricularia species) in recent years
Fun Fact
The Jelly Ear fungus has a fascinating and somewhat macabre etymology rooted in Christian folklore: • The Latin name "auricula-judae" means "ear of Judas" — according to medieval legend, Judas Iscariot hanged himself from an elder tree after betraying Jesus, and the ear-shaped fungi that sprout from elder wood are said to be his lingering, shameful ears • This folk belief was so widespread that in parts of Europe, the fungus was historically called "Oreille de Judas" (French), "Judasohr" (German), and "Judasoor" (Dutch) Remarkable Rehydration Ability: • Dried Jelly Ear can absorb up to 10–15 times its dry weight in water, swelling back to a texture remarkably similar to the fresh fungus • This property made it an ideal food for long-term storage and trade throughout ancient China Blood-Thinning Properties: • Jelly Ear contains adenosine and other compounds that have been shown to inhibit platelet aggregation • A notable case study published in 1986 in The New England Journal of Medicine described a patient who experienced excessive bleeding after consuming large quantities of Jelly Ear while taking anticoagulant medication • This led to increased scientific interest in the fungus's potential cardiovascular benefits Ancient Cultivation: • The earliest known written record of Jelly Ear cultivation appears in the Qimin Yaoshu (齐民要术), a Chinese agricultural text written by Jia Sixie around 544 CE — making it one of the oldest documented examples of fungal cultivation in human history • The text describes log-based cultivation methods that are still conceptually similar to modern practices Acoustic Properties: • When a burning piece of dried Jelly Ear is held near a flame, it crackles and pops audibly — a property that led to its use in traditional Chinese medicine as an indicator of purity and quality
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