inflorescence flower perianth (Q1620)

Collectively, all the sterile, primary, lateral organs (tepals, or sepals and/or petals) of a flower; inserted upon the floral axis immediately beneath (proximal to) the reproductive organs (androecium and/or gynoecium) and surrounding them, often protectively; lacking in some taxa; the individual members typically laminar and more or less foliaceous; widely regarded as consisting of the evolutionarily modified leaves of a fertile shoot; the constituent members undifferentiated with respect to one another, or else differentiated into more or less distinct floral envelopes (calyx and corolla), one or the other of which is deemed lacking in some taxa due to evolutionary reduction following differentiation.