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.

---

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

---

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

---

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 calyptra buds to form a mature gametophyte.

From Textbooks • Jan. 1, 2015

Capsule filling the involucre, circumscissile in the middle, the calyptra persistent at its base.

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 Gray, Asa

Stems erect, nearly simple, radiculose; leaves large, convex, orbicular, entire, purplish; cells large; underleaves lance-subulate, entire or subdentate; perianth terminal, oval; calyptra finally long-exserted.

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 Gray, Asa

The young sporogonium is protected by a thick calyptra derived from the tissue of the thallus around the archegonium.

From Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria" by Various

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 Gray, Asa