The sporogonium when nearly mature bursts the calyptra irregularly.    From Wordnik.com.  [Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria"] Reference

A, Leafy shoot (g) bearing a young sporogonium enclosed in the calyptra.    From Wordnik.com.  [Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria"] Reference

B, Similar plant with an almost mature sporogonium; s, seta; f, capsule; c, calyptra.    From Wordnik.com.  [Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria"] Reference

The young sporogonium is protected by a thick calyptra derived from the tissue of the thallus around the archegonium.    From Wordnik.com.  [Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria"] Reference

The calyptra is ultimately burst through, and in early spring the seta elongates rapidly, raising the dark-coloured capsule (fig. 2).    From Wordnik.com.  [Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria"] Reference

B, Longitudinal section of almost mature sporogonium attached to the thallus. in, Involucre; cal, calyptra; f, foot; s, seta; caps, capsule.    From Wordnik.com.  [Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria"] Reference

Further stages of the development of the sporogonium (f) enclosed in the calyptra formed from the archegonial wall (c) and still bearing the neck (h).    From Wordnik.com.  [Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria"] Reference

The terminal cell is always solitary, very often attached to the one next it, which is generally single, obliquely placed, occasionally looking like the dimidiate calyptra capping a young seta.    From Wordnik.com.  [Journals of Travels in Assam, Burma, Bhootan, Afghanistan and the Neighbouring Countries] Reference

Polytrichum Mnio confine eft, fed calyptra ejus, peculiariter pilofa, perpetuum illi dat cbaraSterem.    From Wordnik.com.  [Caroli a Linné equit. aur. de stella polari archiatri regii med. et botan. profess. Upsal. Acad ...] Reference

CULO gibbOf unilocularis 9 univalvjs; cor lyptrata calyptra fubulatay nuam capfuljL operculo 6? calyptra deciduis i tm.    From Wordnik.com.  [Caroli a Linné equit. aur. de stella polari archiatri regii med. et botan. profess. Upsal. Acad ...] Reference

They are different than other Vitaceae in that their petals are joined at the tip and not attached at the base causing them to fall together forming a calyptra.    From Wordnik.com.  [CreationWiki - Recent changes [en]] Reference

(1838), showed a leaf of a Tulip, whose margins were so united that the whole leaf served as a hood, and was carried upwards by the growing flower like the calyptra of a Moss.    From Wordnik.com.  [Vegetable Teratology An Account of the Principal Deviations from the Usual Construction of Plants] Reference

B idem lente auftum, calyptra tefium.    From Wordnik.com.  [Caroli a Linné equit. aur. de stella polari archiatri regii med. et botan. profess. Upsal. Acad ...] Reference

C, calyptra; ar, neck of archegonium; sg ', foot; sg, capsule.    From Wordnik.com.  [Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria"] Reference