Mycena luxaeterna, common name eternal light mushroom, is a species of fungus

Fungus

A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...

 in the Mycenaceae

Mycenaceae

The Mycenaceae are a family of fungi in the order Agaricales. According to the Dictionary of the Fungi , the family contains 10 genera and 705 species. This is one of several families that were separated from the Tricholomataceae as a result of phylogenetic analyses...

 family. The mushrooms have parachute-shaped caps

Pileus (mycology)

The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...

 which start off darkly grayish-brown, changing to grayish-yellow or pale grayish-brown with a pale white ring at the edge when mature, and reach up to 2 cm (0.78740157480315 in) in diameter. Their thin, cylindrical, hollow, fragile stems

Stipe (mycology)

thumb|150px|right|Diagram of a [[basidiomycete]] stipe with an [[annulus |annulus]] and [[volva |volva]]In mycology a stipe refers to the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal...

 up to 8 mm (0.31496062992126 in) in diameter are covered in a thick gel and emit a constant yellow-green bioluminescence

Bioluminescence

Bioluminescence is the production and emission of light by a living organism. Its name is a hybrid word, originating from the Greek bios for "living" and the Latin lumen "light". Bioluminescence is a naturally occurring form of chemiluminescence where energy is released by a chemical reaction in...

 (the caps do not glow). The gills are attached. The mushroom has a slightly radish-like smell and similar slightly bitter taste. It has been assigned the MycoBank

MycoBank

MycoBank is an online database, documenting new mycological names and combinations, eventually combined with descriptions and illustrations. It is run by the Centraalbureau voor Schimmelcultures fungal biodiversity center in Utrecht....

 number MB 515160.

Habitat

The mushroom was discovered in a very limited area of the Atlantic rain forest of São Paulo, Brazil and is known to exist only at this location. It grows on decomposing twigs, rarely on dead leaves or undergrowth, in clusters of two-to-twenty individuals. Dennis Desjardin is credited with the discovery.

Uses

The eternal light mushroom has no known nutritional value, contains no known hallucinogens, and is not reported as having any particular cultural significance. Its extreme rarity means that it has never been used in cooking.