Calyptra is a term used in botany. The calyptra serves to protect the root growing point in penetrating into the soil. Furthermore, the penetration of this into the ground by verschleimende cells.
In mosses Kalyptra called a hood that covers the capsule in many mosses and contribute to their protection. It is caused by the fact that the sporophyte at the beginning of its growth the tissue of the gametophyte, in which it is incurred (usually this will be the Archegonienhals ), and tearing a piece of it contributes to the top.
The calyptra may be designed very differently. In some mosses it is a kind of felt, with others from a membranous cap, still others it falls off quickly.
In seed plants the word Kalyptra denotes a root cap.