What is the Difference Between Operculum and Peristome?

The operculum and peristome are two distinct structures found in mosses, which are nonvascular plants belonging to the phylum Bryophyta. They play crucial roles in the reproduction and spore dispersal of mosses.

• Operculum: This is a cap-like structure that covers the opening of the sporangium or capsule in mosses and fungi. It falls off or splits open when the spores inside the capsule are mature and ready to be dispersed. Operculum can be found in various plants, mosses, and fungi.
• Peristome: This is a ring of tooth-like appendages that surrounds the mouth of the capsule or spore-bearing structures in flowering plants, some fungi, and mosses. In mosses, the peristome is a specialized structure in the sporangium that allows for gradual spore discharge, instead of releasing them all at once. There are two subtypes of peristome: haplolepidous (consisting of a single circle of 16 peristome teeth) and diplolepidous (found in subclass Bryidae, with two rings of peristome teeth—an inner endostome and an exostome).

In summary, the operculum is a cap-like structure that covers the opening of the sporangium or capsule, while the peristome is a ring of tooth-like appendages surrounding the mouth of the capsule or spore-bearing structures. Both structures play essential roles in the reproduction and spore dispersal of mosses.

Comparative Table: Operculum vs Peristome

Here is a table comparing the differences between operculum and peristome:

Both the operculum and peristome are involved in the release of spores from sporangia or capsules in mosses and fungi, but they serve different functions and have distinct structures.