calyptra
Americannoun
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Also called cap. a hood or hoodlike part, as the lid of the capsule in mosses.
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a root cap.
noun
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a membranous hood covering the spore-bearing capsule of mosses and liverworts
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any hoodlike structure, such as a root cap
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In some bryophyte plants, a structure that covers the young sporophyte as it develops within the tissues of its gametophyte parent. The calyptra, which consists of a thickening of the archegonium walls, eventually breaks open as the spore capsule grows.
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See root cap
Other Word Forms
Etymology
Origin of calyptra
1745–55; < New Latin < Greek kalýptra veil, covering, equivalent to kalýp ( tein ) to veil, cover + -tra noun suffix
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.
The calyptra buds to form a mature gametophyte.
From Textbooks ● Jan. 1, 2015
Involucral leaves coalescent into an oblong truncate hairy tube, blended in our species with the calyptra; perianth none.
From The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee by Asa Gray
Thallus 1–2´ long, decumbent or ascending, fleshy, linear-oblong, simple or slightly lobed, the margin sinuate; diœcious; involucre short, lacerate; calyptra cylindric, smooth; capsule brownish, furrowed; antheridia in 2-lobed receptacles.—Wet banks, N. J. to Ohio, and southward.
From The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee by Asa Gray
Capsules short-pedicelled, or sessile on the thallus, or immersed in its substance, free or connate with the calyptra, globose, at length rupturing irregularly.
From The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee by Asa Gray
Longitudinal section of the summit of a shoot bearing a nearly mature sporogonium, sg, still enclosed in the calyptra; ar′, archegonia which have remained unfertilized; st, stem; b, leaf; p, perianth.
From Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria" by Various
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