Tags: Flower
Collectively, sepals and petals form the perianth. The technical term for the envelope that surrounds the reproductive parts of a flower. This enclosure is composed of two concentric units, the outer perianth, or calyx which may be divided into sepals, and the inner perianth, or corolla, which may be divided into petals. Either the calyx or the corolla (or both) may be much reduced or lacking.