In botany, operculum may be used to describe any of the following:

• A flap of the sporangium of a moss, covering the peristome (appendages surrounding the mouth of a moss capsule).
• The cap of the ascus in certain ascomycetous fungi.
• The bud cap covering the flowers of Eucalyptus and Corymbia trees which falls off as they open.
• The covering of a pyxidium (capsule whose upper part falls off when the seeds are released) of a plant, such as the plantain.
• The flared leaflet that prevents a pitcher plant from accumulating rainwater.

See also:Operculum | Plant physiology