Tremella mesenterica

Scientific name:  Tremella mesenterica Retz.
Derivation of name: Trem- means "to shake or tremble."
Mesenter- means "middle intestine."
Synonyms: Tremella lutescens Pers.  
Common name(s):  Witch's butter.
Phylum:   Basidiomycota
Order:   Tremellales
Family:   Tremellaceae
Occurrence on wood substrate: Parasitic on wood decay
fungi, typically on the out-of-sight mycelium in the wood;
clustered on decaying deciduous wood; year-round.   
Dimensions: Fruitbody 2.5-10 cm wide and 3-4 cm high.    
Description: Brain-like to multilobed gelatinous mass; pale
yellow to orange-yellow, dark orange on drying.
Edibility: Edible.
Comments:  Witch's butter can dry down and rehydrate
many times. Compare to Dacrymyces palmatus, a species
similar in appearance. Dacrymyces palmatus grows on
conifer wood and has a white point of attachment. Although
Tremella mesenterica is found on wood, it is actually a
parasite of wood decay fungi colonizing the wood. All
Tremella species are reported to be parasites of wood decay
fungi.

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Figure 1. Irregularly lobed, gelatinous mass of Tremella
mesenterica. Photo © William Roody.

Figure 2. Another view of Witch's Butter. Photo © Pam
Kaminski.

Figure 3. Tremella mesenterica. Photo © George
Barron.