theca

• Nom désignant une enveloppe, une gaine ou une structure contenante, par exemple le sac pollinique ou la capsule de la mousse en botanique, ou l'enveloppe externe de la chrysalide chez certains insectes.

A noun referring to a case, sheath, or enclosing structure, such as a pollen sac or moss capsule in botany, or the outer sheath of the pupa in certain insects.

1. Botanical structureC2formalscientific

   A case or sheath, especially a pollen sac in flowering plants or a capsule in mosses.

   thèque (structure botanique)

   • The theca of the moss capsule splits open to release spores.
   • Each anther contains two thecae that hold pollen grains.
   • Botanists studied the theca structure under a microscope.

   Synonymescapsulecasesacsheathsporangium

2. Insect pupal sheathC2formalscientific

   The outer protective sheath covering the pupa of certain insects.

   Enveloppe nymphale des insectes

   • The insect's theca hardened to protect the developing pupa.
   • Entomologists observed the theca of the butterfly pupa.
   • The theca splits open when the adult insect emerges.