perianth

n. [ Pref. peri- + Gr. 'anqos flower: cf. F. périanthe. ] (Bot.) (a) The leaves of a flower generally, especially when the calyx and corolla are not readily distinguished. (b) A saclike involucre which incloses the young fruit in most hepatic mosses. See Illust. of Hepatica. [ 1913 Webster ]