Auricularia

The genus was first introduced in 1780 by French mycologist Pierre Bulliard for a range of different fungi producing fruit bodies with an ear-like shape. In 1822 Christian Hendrik Persoon restricted the genus to two gelatinous species, Auricularia mesenterica (which became the type species) and A. sambuci (a synonym of Auricularia auricula-judae).[2] In 1848 Swedish mycologist Elias Magnus Fries accepted A. mesenterica within the genus but, on the basis of differences in fruitbody appearance, introduced a new genus, Hirneola, for most other species.[3] This division into two genera was maintained by some authors until at least the 1960s,[4] though American mycologist Bernard Lowy's monograph of the genus had accepted Hirneola as a synonym of Auricularia in 1952 .[5]

Molecular research, based on cladistic analysis of DNA sequences, has shown that Auricularia (including Hirneola) forms a natural, monophyletic grouping. It has also shown that many species are more restricted in distribution than previously thought, resulting in the description of additional new taxa.[6][7][8]

All species of Auricularia form thin, brownish, rubbery-gelatinous fruit bodies that are shelf-like or ear-shaped and up to 120 mm (4.7 in) across and 5 mm (0.20 in) thick. The fruitbodies occur singly or in clusters. The upper surface is finely pilose to densely hirsute. The spore-bearing underside is smooth, wrinkled, veined, or reticulate (net-like).[8] Unpigmented white forms are occasionally encountered.[9][10]

All species grow on wood and are saprotrophic wood-rotters, producing a white rot.[11] Most occur on dead wood, but they can also be weakly parasitic on living wood. The majority of species grow on broadleaf trees and shrubs, but a few grow on conifers. Fruit bodies occur singly, in clusters, or in tiers.[5][8]

The genus has a global distribution, with some species confined to the tropics, others to north temperate regions, and others to south temperate regions.[5][8]

At least three species are commercially cultivated for food on a large scale in China and East Asia. They include Auricularia heimuer (black wood ear), formerly misdetermined as Auricularia auricula-judae;[12][7] Auricularia cornea (wood ear or cloud ear), also called A. polytricha; and Auricularia villosula.[8]

Other species are eaten locally around the world. A study on the use of fungi by the Bini people of southern Nigeria found that the local inhabitants collected and ate a species similar to A. auricula-judae, but that it was not one of the fungi they used medicinally.[13] Collection of Auricularia species has also been documented in Nepal. However, the Nepalese do not consider them all that good for eating; of the three grades given to edible fungi, they were given the worst.[14] Additional places where Auricularia species have been recorded as locally gathered and consumed include Benin, Chile, Fiji, Ghana, Guatemala, India, Indonesia, Madagascar, Mexico, Mozambique, and Poland.[15]

Several species, including the Asian cultivated species and the European A. auricula-judae (jelly ear or jew's ear), have been used in traditional medicine.[16] They have also been investigated for potential pharmaceutical use.[12]