The flower assumes an endless variety of forms, and we shall assume in the dissection merely the typical form of it.

The organs of a flower are of two sorts, viz.: 1st. Its leaves or envelopes; and 2d, those peculiar organs having no resemblance to the envelopes. The envelopes are of two kinds, or occupy two rows, one above or within the other. The lower or outer row is termed the Calyx, and commonly exhibits the green color of the leaves. The inner row, which is usually of more delicate texture and forms the most showy part of the flower, is termed the Corolla. The several parts of the leaves of the Corolla are called Petals, and the leaves of the Calyx have received the analogous name of Sepals. The floral envelopes are collectively called the Perianth.

The essential organs enclosed within a floral envelope are also of two kinds and occupy two rows one within the other. The first of these, those next within the petals, are the Stamens. A stamen consists of a stalk called the Filament, which bears on its summit a rounded body termed the Anther, filled with a substance called the Pollen.

The seed-bearing organs occupy the centre or summit of a flower, and are called Pistils. A pistil is distinguished into three parts, viz.: lst, the Ovary, containing the Ovales; 2d, the Style, or columnar prolongation of the ovary; and 3d, the Stigma, or termination of the style.

All the organs of the flower are situated on, or grown out of, the apex of the flower-stalk, into which they are inserted, and which is called the Torus or Receptacle.

A plant is said to be monoecious, where the stamens and pitils are in separate flowers on the same individual, dioecious, where they occupy separate flowers on different individuals, and polygamous where the stamens and pistils are separate in some flowers and united in others, either on the same or two or three different plants.