noun
pyxidium; pyxis
A botanical term for a type of dry fruit that opens by a lid-like structure, as in plantains and some other plants.
オオバコの実は蓋果で、熟すと蓋が取れて種子がこぼれる。
The fruit of the plantain is a pyxidium; when ripe, the lid comes off and the seeds spill out.