Page:British Flowering Plants.djvu/28

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another by the wind; and very frequently it is transferred from plant to plant by bees and other insects.

The style is sometimes very short, and placed directly on the ovary; but is often very long. It consists of the stigma, on which the pollen-grains fall, and the tube-like stem. Beneath is the ovary. Sometimes the style is absent, and we find only a stigma placed directly on the ovary itself. The stigma is then said to be sessile. The ovary may be—

(a) Superior, when it is placed higher than the calyx, corolla, and stamens (fig. 82).

(b) Medium, when the calyx, corolla, and stamens stand in a pitcher-like prolongation of the axis of the flower (fig. 83).

(c) Inferior, when the calyx, corolla, and stamens stand on the ovary itself (fig. 84).

In double flowers, like garden Roses and Dahlias, the stamens, and in part the styles, are metamorphosed into petals; and such flowers are infertile. The outer flowers of the wild Guelder-rose, and all the flowers of the garden plant, are likewise infertile.

In many flowers the corolla is irregularly tormed.

Among these are the Papiilionaceæ, or butterfly-flowers, such as those of Peas and Beans. They are so called from their resemblance to white butterflies; and the corolla is composed of five petals—one upper (the flag or standard), two lateral (wings), and two lower. The last are generally