Tremella mesenterica

Description
Mushroom Identification
Look-Alikes
Uses
History
Synonyms and Varieties
Video

Description

Tremella mesenterica is a common jelly fungus in the family Tremellaceae of the Agaricomycotina. It grows on dead, attached branches, especially of angiosperms, as a parasite of wood decay fungi in the genus Peniophora. It has a convoluted or lobed, orange-yellow, gelatinous surface that is greasy or slimy when damp. It grows in crevices in bark and appears during rainy weather. It is found in deciduous and mixed forests and is widely distributed in temperate and tropical regions including Africa, Asia, Australia, Europe, North and South America.

It is edible, but considered flavorless. Although some have claimed the fungus to be inedible or merely "non-poisonous", other sources say that it is edible but flavorless. The gelatinous to rubbery consistency lends texture to soups. In China, the fungus is used by vegetarians to prepare "an immunomodulating cooling soup with lotus seed, lily bulbs, jujube, etc."

Biomedical researchers in China discovered that this fungus produces polysaccharides, a type of carbohydrate. For this reason, it is believed to be a powerful immune enhancer.

According to European legend, if yellow brain fungus appeared on the gate or door of a house it meant that a witch had cast a spell on the family living there. The only way the spell could be removed was by piercing the fungus several times with straight pins until it went away. This is why yellow brain also has the common name of 'witches’ butter'. In Sweden, yellow brain fungus was burnt to protect against evil spirits.

Common names: Witch's Butter, Yellow Brain, Golden Jelly Fungus, Yellow Trembler, Tripe fungus, Tremelle jaune (French), Goldgelber Zitterling (German), Gele trilzwam (Netherlands), Huang jin yin er (Chinese), Hida kikurage (Japanese), gullkrös (Swedish), Viltig judasoor (Dutch), Rosolovka mozkovitá (Czech Republic).

Mushroom Identification

Fruiting Body

This mushroom has a mass of lobes or brain-like sections that are 2-5 cm across and 1-3 cm high. Its surface is bald, moist, and ranges in color from dull to bright yellow or orangish-yellow. The flesh is gelatinous and yellow, but it may fade and become amorphous and poorly defined with age or in wet conditions. When dry, it forms an orangish-yellow crust.
Spores

The spores, when viewed in a mass, are white or pale yellow.
Habitat

Grows on the mycelium of certain species of crust fungi and is usually found on the decaying sticks and logs of oaks and other hardwoods, typically when the bark is still attached. It usually appears in spring in temperate areas, but it can also appear in summer, fall, and winter. It is widely distributed in North America and Europe, but it may be less common in western North America. It grows alone or in amorphous clusters.
Microscopic Features

Spores 10–15 x 6–12 µm; ellipsoid; smooth; hyaline in KOH; often "budding" to germinate by repetition, and then sometimes enlarging and/or becoming irregularly shaped. Basidia 21–22 x 12–18 µm; ellipsoid; mostly 4-sterigmate, with long, fingerlike sterigmata (to about 40 µm long); longitudinally septate. Conidia often present; variously sized but usually smaller than spores; ellipsoid to subfusiform; smooth; hyaline in KOH.

Look-Alikes

Dacrymyces chrysospermus

Looks very similar, but grows on conifer wood, and has a lighter-colored or white attachment point where it attaches to the wood it is growing from.
Guepiniopsis alpina

Small fruit bodies can look similar when young.

Uses

Pharmacologically active polysaccharides make up the bulk of the fruit body, 60-90%, while with other medicinal mushrooms the polysaccharides make up a much smaller part of the biomass, 10-30%.
Polysaccharides significantly inhibit cancer cell DNA synthesis and growth in mice
Rich in provitamin D, Vitamin D deficiency is associated with depression and obesity.
Polysaccharides are made up of hemicellulose, a soluble fiber, having a hypoglycemic and hypocholesterolemic effect.
The polysaccharides are known for their water holding capacities
Good for skin elasticity – brew fruiting bodies as a thick gelatinous tea and apply to the skin with a cotton pad. Rinse out after 30 minutes.
Anti-oxidant and immunomodulating, the polysaccharides stimulate macrophage enzyme activity.
Could be used to treat stomach ulcers. Soothing to the GI and has also shown to be effective against H. pylori.
Increased immune function with type 1 diabetic mice
One study, showed a decrease in blood sugar to normal levels for 24 hours.
Ethanol extract caused apoptosis in human lung carcinoma epithelial cells.

History

This jelly fungus was originally described by Swedish botanist Anders Jahan Retzius in 1769. The generic name Tremella means "trembling," which refers to the wobbly, jelly-like structure of the mushroom. The specific epithet mesenterica is derived from Ancient Greek words meaning "middle" and "intestine," suggesting that the fungus resembles a middle intestine more than a brain.