September 2004. Peelings of swamp taro, Cyrtosperma merkusii, make a very good compost, and often produce mushrooms. Is it a Volvariella? The photo was taken at Silolo, north Malaita, Solomon Islands, where the PestNet project email station is located.
The mushroom was confimred as Volvariella volvacea (Plutaceae), the rice straw mushrom. This species also occurs wild in Darwin, and it is edible. It also occurs on Choiseul, where is called loda kurumeme. It is the mushroom that usually grows on rotten sago palm trunks, but can also grow on other media - I have seen them on rotten cocoa pods and banana fibre, rotten copra bags. At least eight species are eaten.
The other genus in the family, Pluteus does not have a universal veil, but similar to Volvariella does emerge from an egg-like sac. Generally, the literature warns against confusing with the deadly Amanitas (Aminataceae), which also has a sac and universal veil.
And from the Global Plant Clinic and list of the edible Volvariella species found worldwide:
Of these only V gloiocephala has reports of being poisonous and even then this is qualified report. The photograph certainly looks like V. volvacea and that is the most commonly encountered species. See
photograph from Vietnam market (above, left) where, presumably, traders were keen to have their customers return.
A photo alone can't confirm this but the fact that it was saprobic (therefore not ectomycorrhizal) suggests it is not Amanita. It doesn't look like any I know.
A databases has been created for Wild Edible Fungi: global uses and importance to people. The book is due out any time now from FAO and in due course the wild useful fungi database will be put on the web, allowing people access to 6000+ records from over 80 countries.