Sepal Sepal A sepal ( or ) is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom. The term "sepalum" was coined by Noël Martin Joseph de Necker in 1790, and derived from the Greek σκεπη ("skepi"), a covering. Collectively the sepals are called the calyx (plural calyces), the outermost whorl of parts that form a flower. The word "calyx" was adopted from the Latin "calyx", not to be confused with "calix", a cup or goblet. "Calyx" derived from
Polygonum ramosissimum calyx. The calyx is around long and 5-parted with the outer three sepals longer than the inner sepals. The seeds are produced in fruits called achenes, which are egg-shaped, dark brown and around long. The achenes also have a smooth shiny surface. The late season achenes are larger, from 4 to 15 mm long. There are a number of forms and two subspecies, that vary in flower and foliage coloration. "Polygonum ramosissimum" has great morphological variability, which is notable on the same plant, between flowers and fruits produced early in the blooming season verses those produced late in the season,