''Auricularia heimuer'', also known as heimuer () or black wood ear, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

fungus A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from th ...

in the order

Auriculariales The Auriculariales are an order of fungi in the class Agaricomycetes. Species within the order were formerly referred to the "heterobasidiomycetes" or "jelly fungi", since many have gelatinous basidiocarps (fruit bodies) that produce spores on ...

. It is commercially cultivated for food in China at a value exceeding $4 billion (USD) per year. The species was previously referred to as the European ''

Auricularia auricula-judae ''Auricularia auricula-judae'', which has the recommended English name jelly ear, also known as Judas’s ear or Jew’s ear, is a species of fungus in the order Auriculariales. Basidiocarps (fruit bodies) are brown, gelatinous, and have a noti ...

'', 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 Hot and sour soup is a popular example of Sichuan cuisine. Similar versions are found in Henan province, near Beijing, and in Henan cuisine itself, where it may also be known as ''hulatang'' or "pepper hot soup" (胡辣汤). North America Un ...

, and it is also used in

traditional Chinese medicine Traditional Chinese medicine (TCM) is an alternative medical practice drawn from traditional medicine in China. It has been described as "fraught with pseudoscience", with the majority of its treatments having no logical mechanism of action ...

Taxonomy

''Auricularia heimuer'' was described in 2014 as a result of

molecular A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioche ...

research, based on

cladistic Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...

analysis of

DNA sequences A nucleic acid sequence is a succession of bases signified by a series of a set of five different letters that indicate the order of nucleotides forming alleles within a DNA (using GACT) or RNA (GACU) molecule. By convention, sequences are usua ...

, into wild and cultivated species of ''

Auricularia ''Auricularia'' is a genus of fungi in the family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maint ...

'' in China. This research revealed that the most frequently cultivated species was previously misdetermined as ''

'', 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), which translates to 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 Trichomes (); ) are fine outgrowths or appendages on plants, algae, lichens, and certain protists. They are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae. A covering of any kind of hair on a plant ...

, coloured fawn to reddish brown when fresh, and coloured grey-brown when dry. The colour of cultivated specimens is often darker. The spore-producing underside is smooth to slightly veined, coloured pinkish buff when fresh, and coloured purplish grey when dry.

Microscopic features

The

basidia A basidium () is a microscopic sporangium (a spore-producing structure) found on the hymenophore of fruiting bodies of basidiomycete fungi which are also called tertiary mycelium, developed from secondary mycelium. Tertiary mycelium is highly-c ...

are cylindrical, 40-65 x 3-6.5 μm, with three transverse

septa The Southeastern Pennsylvania Transportation Authority (SEPTA) is a regional public transportation authority that operates bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly 4 million people in five coun ...

. The

basidiospores A basidiospore is a reproductive spore produced by Basidiomycete fungi, a grouping that includes mushrooms, shelf fungi, rusts, and smuts. Basidiospores typically each contain one haploid nucleus that is the product of meiosis, and they are pro ...

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 A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one or ...

) is normally present.

Similar species

The Asian ''

Auricularia villosula ''Auricularia'' is a genus of fungi in the family Auriculariaceae. Basidiocarps (fruit bodies) are typically gelatinous and ear-shaped, with a slightly downy to conspicuously hirsute upper surface and an under surface that is smooth, wrinkled o ...

'' 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 it is not as dark as cultivated ''A. heimuer'' and microscopically distinguishable 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 the dead standing or fallen wood of broadleaf trees. In the wild, it occurs most frequently on

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

(''Quercus'') trees and less frequently on other broadleaf trees. In cultivation, it is sometimes grown on broadleaf logs, and is more commonly grown on

growing media A growth medium or culture medium is a solid, liquid, or semi-solid designed to support the growth of a population of microorganisms or Cell (biology), cells via the process of cell proliferation or small plants like the moss ''Physcomitrella pat ...

containing sawdust. The species occurs in temperate areas of northern China, as well as 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 The Tang dynasty (, ; zh, t= ), or Tang Empire, was an Dynasties in Chinese history, imperial dynasty of China that ruled from 618 to 907 AD, with an Zhou dynasty (690–705), interregnum between 690 and 705. It was preceded by the Sui dyn ...

(618–907).

Li Shizhen Li Shizhen (July 3, 1518 – 1593), courtesy name Dongbi, was a Chinese acupuncturist, herbalist, naturalist, pharmacologist, physician, and writer of the Ming dynasty. He is the author of a 27-year work, found in the ''Compendium of M ...

, 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 Medicinal fungi are fungi that contain metabolites or can be induced to produce metabolites through biotechnology to develop prescription drugs. Compounds successfully developed into drugs or under research include antibiotics, anti-cancer drugs, ...

. The estimated annual output in China in 2013 was 4.75 billion kg in fresh weight, with a value of about four billion US dollars. Japan: In Japan, the fungus is known as "kikurage" (キクラゲ) (lit. "wood jellyfish"), and is commonly shredded and used as a topping in

ramen is a Japanese dish, Japanese noodle dish. It consists of served in a broth; common flavors are soy sauce and miso, with typical toppings including , nori (dried seaweed), menma (bamboo shoots), and scallions. Ramen has its roots in Chinese ...

. Korea: Commercially cultivated and called "heung-mogi" (흑목이), the fungus is commonly used in

japchae ''Japchae'' () is a savory and slightly sweet dish of stir-fried glass noodles and vegetables that is popular in Korean cuisine. * ''Japchae'' is typically prepared with ''dangmyeon'' (당면, 唐麵), a type of cellophane noodles made from swee ...

References

{{Taxonbar, from=Q107506789 Chinese edible mushrooms Auriculariales Fungi of Asia Medicinal fungi Fungi in cultivation Buddhist cuisine Fungi described in 2014