Tremella mesenterica Pers. ex St.Amans

Common name: Brain Fungus, Yellow Brain Fungus, Yellow Jelly Fungus.

Description: Forms brilliant orange or orange-yellow masses reminiscent of a brain or a cluster of intestines about 520 cm in diameter. The texture is soft and gelatinous while the surface is moist but not slimy.

The spores measure 1014 × 710 µm and are ellipsoidal to broadly ellipsoidal, smooth and colourless, but white in mass.

Substratum: Grows directly on old logs in rainforest, but it has also been seen in eucalypt forest, woodland and (rarely) in humid microhabitats on heath. Occurs singly or as several together. Occasional rare displays have been seen in which perhaps 50 fruiting bodies are clustered over the surface of a dead tree.

Distribution: Widely distributed in Queensland, New South Wales, Victoria and Tasmania.

Notes: Until recently, it was thought this species was a wood-destroying fungus. It is now believed to be a parasite on other wood-destroying fungi present in the log on which it is growing. A very similar species, Tremella aurantia is found in Western Australia but its spores are distinctly very broadly ellipsoid to subglobose and are smaller (8.510 × 78.5 µm).