Auricularia heimuer
Auricularia heimuer (黑木耳 heimuer or black wood ear) is a species of fungus in the family Auriculariales. It is commercially cultivated for food in China at a level exceeding $4 billion (USD) per year. The species was previously referred to the European "Auricularia auricula-judae", but the latter is not known to occur in east Asia. "Auricularia heimuer" is a popular ingredient in many Chinese dishes, such as hot and sour soup, and is also used in traditional Chinese medicine. Taxonomy. Auricularia heimuer was described in 2014 as a result of molecular research, based on cladistic analysis  of DNA sequences, into wild and cultivated species of "Auricularia" in China. This research revealed that the most frequently cultivated species was previously misdetermined as "Auricularia auricula-judae", a species confined to Europe, and was instead a separate and distinctive species restricted to east Asia. It was given the name "Auricularia heimuer" based on the Chinese vernacular name for the fungus: heimuer (黑木耳) black wood ear. Description. Fruitbodies are gelatinous, ear-shaped, and laterally attached to wood. They are up to across and thick. The upper surface is finely tomentose, fawn to reddish brown when fresh, grey-brown when dry . The colour of cultivated specimens is often darker. The spore-producing underside is smooth to slightly veined, pinkish buff when fresh, purplish grey when dry. Microscopic features. The basidia are cylindrical, 40-65 x 3-6.5 μm, with three transverse septa. The basidiospores are allantoid (sausage shaped), 11-13 x 4-5 μm. Hairs on the upper surface are 50-150 x 4-6,5 μm. When cross-sectioned, a medulla (a central band of parallel hyphae) is normally present. Similar species. The Asian "Auricularia villosula" is very similar, but distinguishable microscopically by its shorter hairs (30-70 μm long). Some  strains of "heimuer" cultivated in China have proved to be "A. villosula". The European "Auricularia auricula-judae" is superficially similar, but not so dark as cultivated "A. heimuer" and distinguishable microscopically by its larger basidia and spores, the latter measuring 14.5-18 x 5-6 μm. Fruitbodies of both these species lack a medulla when cross-sectioned. Habitat and distribution. "Auricularia heimuer" is a wood-rotting species, typically found on dead standing or fallen wood of broadleaf trees. In the wild, it occurs most frequently on oak ("Quercus"), less frequently on other broadleaf trees. In cultivation, it is sometimes grown  on broadleaf logs, more commonly on growing media containing sawdust. The species occurs in temperate areas of northern China and is also known from the Russian Far East, Korea, and Japan. Uses. Culinary use. China: The use of an "Auricularia" species, probably "A. heimuer", as a food and a medicine was recorded 2000 years ago in the Chinese medicinal book, "Shennong’s Compendium of Materia Medica". Species were being cultivated in China as early as the Tang dynasty (618–907). Li Shizhen, in his "Pen Tsao Kang Mu", quotes Tang Ying-chuan from that period as saying "put the steamed bran  on logs, cover with straw, Wood Ear will grow". The fungus is widely used as an ingredient in savoury dishes and is also cooked and served as a salad with vegetables and flavourings. A soup containing the species is used medicinally for dealing with colds and fevers in the belief that it reduces the heat of the body. According to a 2010 publication, the annual production of "Auricularia" species worldwide is the fourth highest among all industrially cultivated culinary and medicinal mushrooms. The estimated annual output in China in 2013 was 4.75 billion kg (fresh weight) with a value of  some four billion US dollars. Japan: In Japan the fungus, known as "kikurage" (キクラゲ) (lit. "wood jellyfish"), is commonly shredded and used as a topping in ramen. Korea: Commercially cultivated and called "heung-mogi" (흑목이), the fungus is commonly used in japchae. Pharmacology. "Modern medicinal studies indicated that the extracts of “Heimuer” were effective in anti-aging, lowering blood sugar and fat, improving immunity, and preventing and treating various cancers."