The
perianth (sometimes called perigonium or perigon) is the non-reproductive part of the
flower, and structure that forms an envelope surrounding the sexual organs, consisting of the
calyx (
sepals) and the
corolla (
petals). The term perianth is derived from the
Greek περί,
peri, meaning around, and άνθος,
anthos, meaning flower, while perigonium is derived from
gonos, meaning seed, i.e. sexual organs. In the
mosses and
liverworts (Marchantiophyta), the perianth is the sterile tubelike tissue that surrounds the female reproductive structure (or developing
sporophyte).