A gelatinous mass of brain-like lobes 2 to 7.5 cm across, deep yellow to orange, translucent and slimy when wet, a hard crust when dry.
- Size
- Up to 7.5 cm across.
- Edibility
- Edible but tasteless; in China it goes into a soup.
- Where it grows
- On dead branches in temperate and tropical forests, where it lives off Peniophora, a crust fungus that rots the wood.
- Rain and drought
- Dry, it shrinks to a thin hard film; after rain it swells back into its soft lobes.
- Look-alikes
- Tremella aurantia, matte with thicker lobes and growing on Stereum hirsutum, and Dacrymyces chrysospermus, smaller and on conifer wood.
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- Family
- Tremellaceae
- Order
- Tremellales
- Lifestyle
- A parasite of other fungi, not of the wood. It also lives as a yeast.
- Spores
- Whitish to pale yellow in mass; spores 10 to 16 by 6 to 9.5 µm.
- Chemistry
- Glucuronoxylomannan, a sugar polymer with biological activity in laboratory studies.
- Described
- In 1769, from Sweden, by Retzius. Mesenterica means "of the middle intestine", for its folds.
Commonly associated with
- Witches
- Swedish folklore
- Rain
- Folk names
- Witches' butter, yellow brain.
In folklore
Its folk name comes from the witch trials of Sweden: witches were said to send magic creatures, "carriers", to steal milk and butter from the neighbors, and the yellow jelly on a fence or a gate was the "butter of the witches" those creatures threw up.
Curious fact
A few days after the rain it is only a dry film on a branch, easy to miss; the next rain brings it back to life.
Folklore and traditional associations. They vary between sources and are beliefs, not scientific claims.