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Tremella mesenterica: Witch's Butter

[ Basidiomycetes > Tremellales > Tremellaceae > Tremella ... ]

by Michael Kuo

This common jelly fungus grows from the dead wood of hardwoods, and can be found throughout North America. The species name "Tremella mesenterica" can be applied in a broad, field-guide sense to a handful of species that must be separated microscopically--but in the strictest sense, Tremella mesenterica has elliptical spores measuring 12-16 x 9-10 µ; basidia measuring 20-31 x 16-22 µ; and sparse, thin-walled hyphidia.


Ecology: Parasitic on the mycelium of species of Peniophora (resupinate crust fungi); found on the decaying sticks and logs of oaks and other hardwoods (usually when bark is still adnate); growing in amorphous clusters; spring, summer, fall, and winter; widely distributed in North America.

Fruiting Body: Gelatinous; when young and fresh composed of lobes or brainlike sections, but rather formless in age or in wet weather; up to about 5 cm across; orange to yellow, fading when mature or when wet; without a stem; sometimes becoming tough and crustlike when dried out.

Spore Print: Whitish or pale yellowish.

Microscopic Features: Spores 10-15.5 x 7-12 µ; elliptical to oval; smooth; often "budding" to germinate by repetition. Basidia 4-sterigmate; longitudinally septate; 20-31 x 16-22 µ; sterigmata to about 100 µ long. Vesicles present. Hyphidia sparse; thin-walled; hyaline.

REFERENCES: Retzius, 1769. (Sacardo, 1888; Atkinson, 1900; Lowy, 1971; Wong & Wells, 1985; Arora, 1986; Lincoff, 1992; Metzler & Metzler, 1992; Horn, Kay & Abel, 1993; Zugmaier et al., 1994; Bandoni & Ginns, 1998; Chen, 1998; Barron, 1999; Roody, 2003; McNeil, 2006; Miller & Miller, 2006; Binion et al., 2008.) Herb. Kuo 04179501.

Tremella lutescens is a synonym (see Wong & Wells, 1985). The similar looking Tremella aurantia is parasitic on Stereum hirsutum, growing on conifer wood; it has smaller spores and basidia, and lacks vesicles. Dacrymyces palmatus is another look-alike, but it grows on conifer wood, is smaller, has a tough, white point of attachment, and usually demonstrates colors that are more orange. It is also microscopically distinct; its basidia are Y-shaped.

Further Online Information:

Tremella mesenterica at Tom Volk's Fungi


Tremella mesenterica

Tremella mesenterica

Tremella mesenterica

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Kuo, M. (2008, November). Tremella mesenterica: Witch's butter. Retrieved from the MushroomExpert.Com Web site: