Where is the peridium?

The peridium is the outer layer or protective covering of certain fungi, particularly those in the group of mushrooms known as puffballs. It is typically found encasing the spore-producing structure, helping to protect the spores until they are ready to be released. In some species, the peridium can be tough and hard, while in others, it may be more fragile and soft. Its primary function is to safeguard the developing spores from environmental conditions and predators.