Omphalotus japonicus, commonly known as the tsukiyotake (月夜茸), is an orange to brown-colored gilled mushroom native to Japan and Eastern Asia.

[5] The little-known Lampteromyces luminescens, described in 1979 in China by M. Zang, is similar genetically and may be a synonym, however the taxon is insufficiently known to confirm this.

Kawamura reported that the fungi can be seen from 30 m (100 ft) away at night, and that 100 square centimetres of glowing mushrooms allowed him to read Roman characters of 8 mm size by their light.

[7] This fungus is mistaken for the commonly eaten oyster mushroom (Pleurotus ostreatus), Shiitake (Lentinula edodes), and Mukitake (Sarcomixa serotina), but is poisonous.

[9] The fungus grows on dead beech trees, and is found in mountainous regions of Japan, the fruit bodies appearing in September and October.