You’re walking along one day, you look down and something strange catches your eye. You find a piece of wood that looks like it’s been stained blue. At first, you think there’s something wrong with your eyes. You do a double-take. You do a triple-take. But there it is, blue wood sitting on the forest floor and you think to yourself “how is this possible?”
Well, the blue wood isn’t as odd as you think. It has been stained, but it’s not people doing the staining, it’s a fungus, Chlorociboria aeruginascens. Known as the green elfcup fungus, C. aeruginascens is a wood decomposer with a bright greenish-blue color that likes to do a little fungal graffiti, leaving it’s color in the following season after colonizing newly dead wood. The fruiting bodies of this fungus aren’t commonly seen, and even when they are present their small size–around 0.5 centimeters in diameter and height of less than 0.4 millimeters–makes it difficult to find the cup-shaped mushrooms. While this fungus will colonize almost any dead wood, it is preferential to oak.
Mushrooms of this species are typically found in the summer into the fall throughout North America, but the blue wood can be found any time of year. The green elfcup’s pigment is called xylindein, and it is used in decorative woodworking today. The beautiful wood produced from the fungi can range from greenish to deep blues, just an example of intricate beauty in the natural world.