Calyx

noun

(Gr. kalyx: calyx) (pl. calyces, calyxes) The outer perianth whorl; a collective term for all of the sepals of a flower; the outer covering of a flower external to the corolla, which it encloses, and consisting of a whorl of leaves, or sepals, usually of a green color and less delicate in texture than the corolla; the calyx encloses the petals, stamens, and carpels and protects the flower in bud. See also pappus.