Elfin Gold is another name for cave moss or luminous moss (Schistostega pennata)—a small plant with reflective, somewhat spherical cells at its tips. Native to the Northern Hemisphere, this moss gives off an eerie gold and greenish glow. The luminosity is caused by the reflection of light from the chlorophyll in the filament growing from the plant’s germinating spore. Most often it forms green mats in caves, or cavities in wood, between rocks, or tree roots. In Japan, the plant has been the subject of numerous books, television shows, newspaper and magazine articles, and even an opera. A national monument to this species is located near the coast of Hokkaido, where the moss grows near a small cave.