peristome
Americannoun
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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.
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Zoology. any of various structures or sets of parts that surround or form the walls of a mouth or mouthlike opening.
noun
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a fringe of pointed teeth surrounding the opening of a moss capsule
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any of various parts surrounding the mouth of invertebrates, such as echinoderms and earthworms, and of protozoans
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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.
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The area or parts around the mouth in certain invertebrates, such as the echinoderms.
Other Word Forms
Etymology
Origin of peristome
From the New Latin word peristoma, dating back to 1790–1800. See peri-, -stome
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
A structure called a peristome increases the spread of spores after the tip of the capsule falls off at dispersal.
From Textbooks ● Jan. 1, 2015
In mosses the teeth of the peristome are arranged in fours, or in some multiple of that number.
From Vegetable Teratology An Account of the Principal Deviations from the Usual Construction of Plants by Masters, Maxwell T.
More usually there is a peristome, consisting of one or two series of teeth, which serves to narrow the opening and in various ways to ensure the gradual shedding of the spores in dry weather.
From Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria" by Various
Bütschli, following Quennerstedt, describes an undulating membrane on each side of the peristome groove.
From Marine Protozoa from Woods Hole Bulletin of the United States Fish Commission 21:415-468, 1901 by Calkins, Gary N. (Gary Nathan)
The peristome begins as a shallow furrow at the center of the ventral surface and dips sharply into the buccal depression, which is deep and turned toward the posterior end.
From Marine Protozoa from Woods Hole Bulletin of the United States Fish Commission 21:415-468, 1901 by Calkins, Gary N. (Gary Nathan)
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
