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

Thallus pinnately divided or subsimple, flat or somewhat channelled; branches horizontal, the broader pinnatifid or dentate, obtuse; calyptra somewhat smooth.—On dripping rocks, Hokokus, N. J.

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

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

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

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 Gray, Asa