calyptra

名词noun

1. 1(botany) In bryophytes, a thin hood of tissue that forms from the archegonium and covers the developing sporophyte and is shed as it ripens.
2. 2(botany) any cap-like covering of a flower or fruit, such as the operculum over the unopened buds of Eucalyptus flowers
3. 3(botany) Any of various coverings at the tips of structures, in the terminology of various authors; for example rootcaps