Japan's rainy season, a mysterious type of green, glow-in-the-dark mushroom begins to sprout in Wakayama prefecture. The Mycena lux-coeli mushrooms, known locally as shii no tomobishi-dake (literally, "chinquapin glow mushrooms"), sprout from fallen chinquapin trees. As they grow, a chemical reaction involving luciferin (a light-emitting pigment contained within the mushrooms) occurs, causing them to glow a ghostly green. The luminescent mushrooms were long believed to be indigenous solely to Tokyo's Hachijojima Island after they were discovered there in the early 1950s. In 1995, however, mycologists found the fungus growing wild in coastal areas of the southern Kii peninsula, as well as in Kyushu and other areas. The mushrooms thrive in humid environments, popping up during Japan's rainy season, which typically lasts from the end of May to July. The caps can grow to as large as 2 cm (about 1 inch) in diameter, but because the mushrooms are prone to dehydration, they only have a few days to live once the rain stops.