Flowers are the sites of sexual reproduction in flowering plants. Their component parts are arranged
in whorls around the receptacle (tip of the flower stalk). The sepals (collectively called the calyx) are outermost; typically small and green, they protect the developing flower. The petals (collectively called the corolla) are typically large and brightly colored; they are found inside the sepals. In monocotyledonous flowers (see pp. 126-127), sepals and petals are indistinguishable; individually they are called tepals (collectively called the perianth). The petals surround the male and female reproductive structures (androecium and gynoecium). The androecium consists of stamens (male organs); each stamen is made up of a filament (stalk) and anther. The gynoecium has one or more carpels (female organs); each carpel consists of an ovary, style, and stigma. Some flowers (e.g., lily) occur singly on a pedicel (flower stalk); others (e.g., elder, sunflower) are arranged in a group (inflorescence)on a peduncle (inflorescence stalk).
