peristome

[ per-uh-stohm ]

noun

1. 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.
2. Zoology. any of various structures or sets of parts that surround or form the walls of a mouth or mouthlike opening.

peristome

/ ˈpɛrɪˌstəʊm /

noun

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

peristome

/ pĕr′ĭ-stōm′ /

1. 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.
2. The area or parts around the mouth in certain invertebrates, such as the echinoderms.

Derived Forms

• ˌperiˈstomal, adjective

Other Words From

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

Word History and Origins

Origin of peristome¹

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

Word History and Origins

Origin of peristome¹

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

Example Sentences

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

From Project Gutenberg

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

From Project Gutenberg

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

From Project Gutenberg

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

From Project Gutenberg

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

From Project Gutenberg