peristome

[ per-uh-stohm ]

Phonetic (Standard)IPA

noun

Botany. the one or two circles of small, pointed, toothlike appendages around the orifice of a capsule or urn of mosses, appearing when the lid is removed.
Zoology. any of various structures or sets of parts that surround or form the walls of a mouth or mouthlike opening.

peristome

/ ˈpɛrɪˌstəʊm /

a fringe of pointed teeth surrounding the opening of a moss capsule
any of various parts surrounding the mouth of invertebrates, such as echinoderms and earthworms, and of protozoans

peristome

/ pĕr′ĭ-stōm′ /

A fringe of toothlike appendages surrounding the mouth of the spore capsule of some mosses. The teeth unfold under damp conditions and curl up under dry conditions to disperse spores gradually.
The area or parts around the mouth in certain invertebrates, such as the echinoderms.

peri·stomal per·i·sto·mat·ic [per-, uh, -st, uh, -, mat, -ik], peri·stomi·al adjective

From the New Latin word peristoma, dating back to 1790–1800. See peri-, -stome

C18: from New Latin peristoma, from peri- + Greek stoma mouth

The “mouth” or peristome is normally black, the shell larger and stouter than hortensis, in which the mouth is white.

The inner lip is that side of the peristome adjacent to the central pillar of the shell.

The capsules of the mosses form very beautiful microscopic objects, especially those furnished with a toothed peristome.

The capsule (fig. 5) is roundish-ovate, without a peristome, and the operculum is flattened.

In this moss the peristome is single (fig. 18), consisting of thirty-two spirally twisted teeth, arranged in pairs.

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