Structure generally in the shape of a tube, cup, or bowl, derived from the fused lower portions of the perianth and stamens, from which these parts seem to arise, and to which the ovary wall is fused in an inferior ovary (to which the ovary wall is partially fused in a half-inferior ovary; from which the ovary is free in a superior ovary).1
Flowers of Decodon verticllatus. H = hypanthium
1. From Jepson Manual Glossary [Accessed 29 Aug. 2008]