This is a close-up picture that I took earlier this month near the Appalachian Trail in Central Pennsylvania of a very tiny fungus with an adorable moniker and a long pedigree for human use. Called “green elfcup” or “green wood cup,” the technical name of this mushroom is “Chloriciboria aeruginascens,” and although it is a common fungus, it isn’t so common to see the fruiting bodies you see here.
For one, green elf cups are super small — like, 2-6 mm in diameter. Two species of Chloriciboria live in North America, but there are 15 in New Zealand, which given how enchanting the mushroom is, doesn’t surprise me a bit.
The green elf cups grow on decaying hardwood trees like oak, and as they colonize the wood they stain it with the glowing blue-green hues you see here. This colored wood was highly prized in Europe, and Renaissance woodworkers used it in expensive and luxurious compositions such as you see in the second and third images. English woodworkers used it in a type of box making known as “Tunbridge Ware,” in the Victorian era.
Today, at the Center for Forest Mycology Research in Madison, Wisconsin, scientists are studying how to grow these green elf cups in controlled conditions. They have potential non-aesthetic uses like deterring termites, as an algaecide, and as a cancer-fighter.
Source(s): Tom Volk’s Fungus of the Month for July 2008 by Jessie Glaeser and Tom Volk @botit.botany.wisc.edu/toms_fungi/jul2008.html. Third image from Wikipedia ‘cheb relief intarsia’ by Adam Eck, from 1620-1660
