calyptra


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calyptra

[kə′lip·trə]
(botany)
A membranous cap or hoodlike covering, especially the remains of the archegonium over the capsule of a moss.
Tissue surrounding the archegonium of a liverwort.
Root cap.
References in periodicals archive ?
The capsules are clearly visible in this photo (taken in Michigan, USA), and are dark, round, and lack a calyptra.
and E-class MADS-Box homologues in Eupoma-tia (Eupomatiaceae): support for the bracteate origin of the calyptra.
By virtue of its subumbellate inflorescence, Marcgraviastrum is similar to Marcgravia, but differs from this genus in having 5-merous flowers (4-merous in Marcgravia), petals free or variously connate (completely connate into a calyptra in Marcgravia), and leaves spirally arranged (distichous in Marcgravia).
The rupturing ring zone divides the calyptra from the root body, whose future outer layer differentiates as the rhizodermis, whereas the calyptra dissolves steadily on its surface, thus giving the rhizodermis free (Figs.
Calyx lobes ciliate, persistent; corolla sympetalous, cylindrical, the lobes either fused to form a calyptra that splits transversely and falls at anthesis to leave a persistent basal ring, or lobes free and the corolla tube sometimes constricted at the throat.