Terry Burress, age 12, of Canton, N.C.,, for the question:

What is fox‑fire?

Pox‑fire is an eerie glow sometimes seen in a damp woods. It appears after dark and might be mistaken for a frolicsome ghost playing hide and seek or lurking among the tree trunks and fallen logs. Fox‑fire has scared plenty of timid folks and given rise to all manner of ghostly tales.

Of course, the eerie glow is not caused by any member of the spirit world. It comes from saprophytic fungi, a humble cousin of the mushroom and the toadstool. The saprophytic is a wood‑rotting fungus. It sets up housekeeping in fallen logs, damp bark or areas where a tree has been wounded. Its mycelium, the threadlike system which it feeds, digests its food from the bark or wood.

The ghostly light is given off during respiration. Some of the energy released in this process is light energy. In the daytime it goes unnoticed. At night there is just enough light to throw a Halloween scare into a timid traveler.