perianth

thumb|upright=1.4|A mature flower. In this example, the perianth is separated into a calyx (sepals) and corolla (petals)

The perianth (perigonium, perigon or perigone in monocots) is the non-reproductive part of a flower. It is a structure consisting of the calyx (sepals) and the corolla (petals); in perigones it consists of the tepals. It forms an envelope surrounding the sexual organs,. The term perianth is derived from Greek περί (, "around") and άνθος (, "flower"), while perigonium is derived from περί () and γόνος (, "seed, sex organs"). In the mosses and liverworts (Marchantiophyta), the perianth is the sterile (neither male nor female) tube-like tissue that surrounds the female reproductive structure or developing sporophyte.