Omphalotus nidiformis

The ghost fungus (Omphalotus nidiformis) is a gill mushroom found in southern Australia most notable for its bioluminescent properties. Its scientific name is derived from the Latin nidus "nest", hence "nest shaped". Similar in appearance to the oyster mushroom, it was previously considered a member of the same genus, Pleurotus, and described under the former names Pleurotus nidiformis or Pleurotus  lampas. However, it is poisonous and while not lethal, consuming this mushroom leads to very severe cramps, vomiting, and diarrhea. Poisonings have occurred over confusion with oyster mushrooms.

Several species with similar bioluminescent properties occur worldwide, all of which are poisonous. The best known are the North American jack o'lantern mushroom (Omphalotus olearius) and the Tsukiyotake (Omphalotus japonicus (Kawam.) Kirchm. & O.K. Mill., aka Lampteromyces japonicus (Kawam.) Sing.) found in Japan and eastern Asia. A recent molecular study shows the ghost fungus to be most closely related to the western jack o'lantern mushroom, Omphalotus olivascens, which is abundant in Southern and Central California.

Description
The fruiting body of the ghost fungus can be found on dead or diseased wood, where it causes white heart rot. A saprobe or parasite, it is nonspecific in its needs and can be found on native Banksia, Hakea or Acacia and various Myrtaceae as well as introduced trees such as Pinus or Platanus species.

The cap is generally cream in colour, though often tinted with orange, brownish, greyish or purple shades. Growing up to 25 cm in diameter it is funnel-shaped or fan-shaped in appearance. The cream-white gills are decurrent and often drip with moisture. The stubby stem is 2-7 cm long and tapers to the base. The thin flesh is creamy white in colour. There is no distinctive smell or taste. The spore print is white.

Its bioluminescence is best seen in low-light conditions when the eye develops night vision. The gills are the most luminescent part of the fungus, emitting a greenish light which fades with age. The light allegedly can be bright enough to read by.

Distribution and habitat
It occurs in south western Western Australia, where it was first recorded in 1841 by James Drummond, and south eastern Australia, from eastern South Australia through to southeast Queensland. It also occurs in Tasmania.