calyptra n : the hood or cap covering the calyx of certain plants: e.g., the California poppy
In bryophytes, the calyptra is an enlarged archegonia venter that protects the capsule. This cap is lost at maturity. In flowering plants, the calyptra is a covering tissue for stamens and carpels. The name is also used for the capping tissue of roots.
calyptra in German: Kalyptra
calyptra in Dutch: Calyptra