Pollination of the canna flower by bumblebee.
Canna flower.
Pollen on style,
stamen at left.
[CHAPTER XLIV.]
THE FRUIT.
[I. Parts of the Fruit.]
867. After the flower comes the fruit.—With the perfection of the fruit the seed is usually formed. This is the end towards which the energies of the plant have been directed. While the seed consists only of the ripened ovule and the contained embryo, the fruit consists of the ripened ovary in addition, and in many cases with other accessory parts, as calyx, receptacle, etc., combined with it. The wall of the ripened ovary is called a pericarp, and the walls of the ovary form the walls of the fruit.
868. Pericarp, endocarp, exocarp, etc.—This is the part of the fruit which envelops the seed and may consist of the carpels alone, or of the carpels and the adherent part of the receptacle, or calyx. In many fruits the pericarp shows a differentiation into layers, or zones of tissue, as in the cherry, peach, plum, etc. The outer, which is here soft and fleshy, is exocarp, while the inner, which is hard, is the endocarp. An intermediate layer is sometimes recognized and is called mesocarp. In such cases the skin of the fruit is recognized as the epicarp. Epicarp and mesocarp are more often taken together as exocarp.
In general fruits are dry or fleshy. Dry fruits may be grouped under two heads. Those which open at maturity and scatter the seed are dehiscent. Those which do not open are indehiscent.