Field and Woodland Plants

by William S. Furneaux

A leaf or scale will often be observed at the foot of a flower stalk or at the base of a sessile flower. This is termed a bract, and a flower possessing a bract is said to be bracteate. The bract is sometimes so large that it almost completely encloses the flower, or even a cluster of flowers.

Inferior (1) and Superior (2) Ovary.

The flower is the reproductive part of the plant, being concerned in the production of the seeds; but the organs directly connected with the seed-formation are the pistil and the stamens, the former containing the ovules, and the latter producing the pollen cells by means of which the ovules are impregnated. Thus the stamens and the pistil are the essential parts of the flower, though the corolla and the calyx may perform some subsidiary function in connexion with the reproduction of the species.

This being the case, a flower may be described as perfect if it consists of stamens and pistil only, without any surrounding calyx or corolla; and imperfect if it possesses no pistil or no stamens, regardless of the presence or absence of calyx and corolla.

Unisex Flowers of the Nettle
1. Pistillate. 2. Staminate.

The two outer whorls of a well-developed perfect flower (calyx and corolla) together form the perianth. Some flowers, however have only one whorl outside the anthers, representing both the calyx and corolla of the more highly organised flower. This one whorl, therefore, is the perianth, and its parts are not correctly termed either petals or sepals, since they represent both.

A perfect flower is sometimes spoken of as bisexual, for it includes the two sexual organs of the plant—the ovary or female part, producing the ovules; and the stamens or male part, which is concerned in the impregnation or fertilisation of the ovules.

Many plants produce only unisexual (and therefore imperfect) flowers, which contain either no stamens or no pistil. If such possess stamens and no pistil, they are called staminate or male flowers; and if pistil and no stamens, pistillate or female flowers. These two kinds are sometimes borne on the same plant, when they are said to be monœcious; but often on separate plants (diœcious), as in some of the Nettleworts and the Willow Tree. Spikes of unisexual flowers, such as are common among our forest trees, are called catkins.