calyptra

American  

[kuh-lip-truh] / kəˈlɪp trə /

noun

Botany.

1. Also called cap.  a hood or hoodlike part, as the lid of the capsule in mosses.

2. a root cap.

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calyptra British  

/ kəˈlɪptrə, kəˈlɪpˌtreɪt /

noun

1. a membranous hood covering the spore-bearing capsule of mosses and liverworts

2. any hoodlike structure, such as a root cap

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calyptra Scientific  

/ kə-lĭp′trə /

1. 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.

2. See root cap

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Other Word Forms

• calyptrate adjective

Etymology

Origin of calyptra

1745–55; < New Latin < Greek kalýptra veil, covering, equivalent to kalýp ( tein ) to veil, cover + -tra noun suffix

Example Sentences

The ripped-off piece of its birthplace often remains stuck to the top of the sporophyte and is called a calyptra.

From Scientific American

If not preserved in an envelope the calyptra and operculum are very apt to fall off and become lost.

From Project Gutenberg

Thallus decumbent, irregularly lobed, 1–2´ long, 3–5´´ wide; involucre none; pedicel ¾–1´ long, sometimes folded upon itself and remaining within the calyptra, the capsule thus appearing sessile; antheridia on elongated receptacles.—Wooded swamps.

From Project Gutenberg

The calyptra or veil is remarkably small, smooth, and membranous.

From Project Gutenberg

D, capsules of Bartramia: i, with; ii, without the calyptra.

From Project Gutenberg