Stamens in one bundle, Monadelphous. Stamens in two bundles, Diadelphous. Stamens in more than two bundles, Polyadelphous. Filaments placed directly below the pistil, Hypogynous. Placed upon the sides of the calyx, Perigynous. On the sides of the corolla, Epipetalous. On the top of the ovary, Epigynous. When the ovaries are fertilised the flower dies and they begin to enlarge and ripen to form the fruit, which is the pistil enlarged, and contains the ovules ripened into seeds. The fruits of different plants are known by various names according to the state of development of the various parts composing them. If the ripe fruit split open so as to let out the seeds (as in the common pea) it is called "dehiscent," if it do not so split (as in the apple) it is said to be "indehiscent;" the outer part of fruit is called the "pericarp," and this may be soft and fleshy as in the apple or cherry, or hard as in the filbert. The following are the names of the principal varieties of fruit:-- [Illustration: Pome (Apple). Gland (Acorn). Legume (Pea). Stobule (Hop). Drupe (Plum). Berry (Currant). Capsule (Poppy). Siliqua (Shepherd's Purse, Wallflower). Eterio (Strawberry). Nut (Hazel-nut). Caryopsis (Wheat).] The seed is the ovule ripened, it contains the germ of the future plant, called the "embryo," the outer part of the seed is called the "testa," and the space between this and the embryo is generally filled with starchy matter called the "albumen." The embryo consists of the plumule or stem, the "radicle" or root, and the cotyledons or leaves of the future plant; when the seed has but one cotyledon it is called "monocotyledonous" and when it has two "dicotyledonous." Flowers are arranged in various ways upon the plants which produce them, and receive names accordingly; the whole arrangement of flowers is called the "inflorescence." The following are the principal forms of inflorescence:-- [Illustration: Hemlock.] The UMBEL, in which all the flower-stalks (pedicels) radiate from one point, as in the carrot (daucus carota). Umbels are sometimes compound, that is, the flowers are placed in umbels at the end of stalks themselves radiating from a point and so forming an umbel, as in the Hemlock (Conium maculatum). [Illustration: Plantain.] The SPIKE, is that kind of infloresence in which all the flowers are seated without stalks upon a general peduncle or axis, as in the Plantain (Plantago media), in which the spike is entire, or as the Lavender (Lavandula Vera), in which the spike is interrupted, that is, the inflorescence is not continuous. [Illustration: Hazel] CATKIN, or AMENTUM, is the same as a spike, but in which the flowers are imperfectly developed, as in the Hazel (Corylus), Willow (Salix), White Poplar (Populus Alba), &c. [Illustration: Water-cress]