Bryant is again the author of today's entry:
Thank you to Ken Beath (aka kjbeath@Flickr) for today's image of Cyttaria gunnii (commonly known as beech orange), the next subject on the list for this series on autumn fungi. Cyttaria gunnii is an ascomycete in the family Cyttariaceae. It is a caulicolous (stem parasite) fungi, restricted to species of Nothofagus, specifically Nothofagus cunninghamii, Nothofagus fusca, and Nothofagus menziesii. The species is distributed throughout Australia, New Zealand, and Tasmania wherever host trees are also found. The fruiting bodies, which grow in clusters, are usually around 2cm in diameter. The yellow/orange cup-shaped cavities form upon maturity to release wind-dispersed spores.
If infected by Cyttaria gunnii, spherical galls are formed on the host tree. These galls remain on the branch or stem for its lifetime and provide the location for perennial fruiting every spring. Formation of the galls starts with spores germinating and subsequently penetrating the bark tissue of a nearby host, releasing chemicals as the fungal hyphae grows. These chemicals cause the unregulated proliferation of cells in the tree, much like a tumor.
Cyttaria gunnii is considered to be edible, and has been recorded as being used for food by Australian Aboriginals. It is reported to have a pleasant but slightly bland taste (again, consumption is not recommended without confirming identification with an expert).