What does peristome mean?
A peristome is a fringe-like ring of structures around the mouth of an organism. Its best-known use is in bryology, the study of mosses: the mouth of a moss capsule is often bordered by a row of tiny teeth called the peristome teeth. These structures respond to moisture, changing position as humidity rises or falls and thereby helping regulate the release of spores. In zoology, the term describes the cilia surrounding the oral region of a ciliate, which can move food toward the cell's mouth. The word is therefore associated with both delicate botanical structures and the feeding apparatus of microscopic animals. Although technically precise, it is not normally used in everyday speech.
nounA ring of minute structures surrounding the mouth of a moss capsule or a certain ciliate protozoan. In mosses, the peristome commonly consists of hygroscopic teeth that help regulate the release of spores.
- The fringe or ring of small, usually tooth-like structures around the mouth of a moss capsule.
- The ring of cilia surrounding the oral region of a ciliate protozoan.
"Changes in humidity make the peristome teeth of the moss curl and uncurl, helping control when spores escape from the capsule."
"The researcher examined the peristome under a microscope and counted its regularly arranged teeth."
"The ciliate uses its peristome to sweep food particles toward the oral opening."
The regular plural is used for multiple mosses, capsules, or ciliates with this structure.
"The botanist compared the peristomes of mosses collected from different habitats."
When a moss capsule opens, its tiny peristome teeth act like a humidity-sensitive gatekeeper, curling and uncurling to control the release of spores.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does peristome come from?
Peristome combines the Greek prefix peri-, meaning “around,” with stoma, meaning “mouth.” The form reflects the word's original sense of a structure arranged around an opening. Its history is closely associated with descriptions of moss capsules, while its components also connect it to other English words built from Greek elements meaning “around” or “mouth.”
How peristome is actually used
The term is used in botany, bryology, and zoology, especially when describing moss capsules and ciliates. It is specialized and uncommon in general English.