- Auricularia auricula Mushrooms Growing Wild - Jacob Whittaker
Auricularia auricula, more properly called Auricularia auricula-judae is commonly called tree ear, black fungus, cloud ear, Jew's ear, Judas's ear, or tree jelly fish. This species is found world-wide in temperate climates.
It doesn't look like food, but it is edible. Easily mistaken for a weird vegetable, many people have eaten it in Chinese food without knowing exactly what it is. It's the brown gelatinous component of hot and sour soup.
Biology of Auricularia auricula
The wood ear is a basidiomycete fungus, but its fruit bodies are not typical "mushrooms." The rubbery ear-like reproductive structures appear singly or in small groups. They are commonly seen growing on dead wood in North American forests along creek and river banks.
The basidiocarps are dark brown throughout with no visible gills, sometimes with a fine white fuzzy covering. They turning dark purple to black when dry. Unlike gilled mushrooms, which eject their spores into the space between the gills, Auricularia spores must work their way through a tough layer to reach the air for dispersal. It can be tricky to get a spore print from a wood ear, but when obtained the spore print is white to creamy yellow in color.
Auricularia is said to form mycorrhizae, a mutualistic relationship between the fungus and the roots of certain trees. This is unusual since the mushrooms of most mycorrhizal fungi appear in or on the ground surrounding their host trees. The fruit bodies grow according to a habit more typical of a saprophyte, and are found on the trunks and branches of dead hardwood trees.
Growing Wood Ear Mushrooms
The wood ear is a wild mushroom, but it is also one of the top five commercially produced mushrooms. This is because of its ability to grow as a saprophyte on dead wood. Hundreds of thousands of tons are produced each year, mostly in Asia. Unlike other mycorrhizal fungi, Auricularia is easily grown in commercial volumes using techniques similar to those used to grow Lentinula, the shiitake mushroom. Log or bag culture on hardwood chips and sawdust is the most common production method.
Harvested mushrooms are usually dried for easy transport and storage. They easily rehydrate into a near-fresh state when soaked in water.
Medicinal Value of Wood Ear Mushrooms
The wood ear has been a part of traditional Chinese medicine for centuries. The range of ailments specified for treatment is so broad and varied it is difficult to conceive of how the fungus could be effective for so many unrelated maladies.
Like many mushrooms, Auricularia species contain polysaccharides, some of which are known to be immunostimulatory and inhibitory toward cancer cells. Antiviral, antibacterial and cholesterol lowering effects have also been described, but these are general properties of fungal polysaccharides and there has been little work on these potential activities with respect to Auricularia. Some reputable research has indicated anticancer potential as well as anticoagulant and hypoglycemic effects.
One report notes that drinking tea made from wood ear fungus was popular for a time in Britain, but the extreme acidity of the concoction caused stomach troubles so the practice has been discontinued.
References
"Potential of Fungi Used in Traditional Chinese Medicine: Auricularia", Bonell, A., 2001, World of Fungi.org website, (accessed June 7, 2009).
Mushrooms: Cultivation, Nutritional Value, Medicinal Effect, and Environmental Impact, Chang, S -T, Miles, P.G., 2004, CRC Press, Boca Raton
Growing Gourmet and Medicinal Mushrooms (3rd Edition), 2003, Stamets, P., Ten Speed Press, Berkeley
Philip McIntosh - The author holds a B.Sc. in Botany and Chemistry and an M.A in Biology and he has thirty + years of experience in science and industry.
