SUGGESTIONS.—=8.= The teacher may assign each pupil to one plant in the school yard, or field, or in a pot, and ask him to bring out the points in the lesson. =9.= The teacher may put on the board the names of many common plants and ask the pupils to classify into annuals, pseud-annuals, plur-annuals (or climatic annuals), biennials, perennials, herbaceous perennials, ligneous perennials, herbs, bushes, trees. Every plant grown on the farm should be so classified: wheat, oats, corn, buckwheat, timothy, strawberry, raspberry, currant, tobacco, alfalfa, flax, crimson clover, hops, cowpea, field bean, sweet potato, peanut, radish, sugar-cane, barley, cabbage, and others. Name all the kinds of trees you know. CHAPTER VI SEEDS AND GERMINATION The seed contains a _miniature plant_, or =embryo=. The embryo usually has three parts that have received names: the stemlet, or =caulicle=; the seed-leaf, or =cotyledon= (usually 1 or 2); the bud, or =plumule=, lying between or above the cotyledons. These parts are well seen in the common bean (Fig. 15), particularly when the seed has been soaked for a few hours. One of the large cotyledons—comprising half of the bean—is shown at _R_. The caulicle is at _O_. The plumule is shown at _A_. The cotyledons are attached to the caulicle at _F_: _this point may be taken as the first node or joint_. [Illustration: FIG. 15.— PARTS OF THE BEAN. _R_, cotyledon; _O_, caulicle; _A_, plumule; _F_, first node.] =The Number of Seed-leaves.=—All plants having _two seed-leaves_ belong to the group called =dicotyledons=. Such seeds in many cases split readily in halves, _e.g._ a bean. Some plants have only _one_ seed-leaf in a seed. They form a group of plants called =monocotyledons=. Indian corn is an example of a plant with only one seed-leaf: a grain of corn does not split into halves as a bean does. Seeds of the pine family contain more than two cotyledons, but for our purposes they may be associated with the dicotyledons, although really forming a different group. These two groups—the dicotyledons and the monocotyledons—represent two great natural divisions of the vegetable kingdom. The dicotyledons contain the woody bark-bearing trees and bushes (except conifers), and most of the herbs of temperate climates except the grasses, sedges, rushes, lily tribes, and orchids. The flower-parts are usually in fives or multiples of five, the leaves mostly netted-veined, the bark or rind distinct, and the stem often bearing a pith at the centre. The monocotyledons usually have the flower-parts in threes or multiples of three, the leaves long and parallel-veined, the bark not separable, and the stem without a central pith. [Illustration: FIG. 16.—EXTERNAL PARTS OF BEAN. ]