Foxfire: During the late summer, a faint, eerie glow can be seen in forests around the world, where bioluminescent mushrooms grow on moist, rotting bark. The greatest diversity of firefox occurs in the tropics, where moist forests encourage fungal growth. The newest varieties of glow-in-the-dark mushrooms were introduced to the world just last year, after being collected from Ribeira Valley Tourist State Park near Sao Paulo, Brazil.