What is peridium?

Peridium refers to the outer layer of the fruiting body of certain fungi, such as puffballs, earth-stars, and stinkhorns. It is usually opaque and thick in texture, serving to protect the spores of the fungus as they mature. The peridium can be divided into several layers, including the outer skin, middle layer, and inner layer. In some species, the peridium will become papery or break apart as the spores mature, while in others, it will remain intact and disintegrate only when the spores are ejected. The appearance, shape, and color of the peridium can vary widely depending on the species of fungus.