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16   FODDER AND PASTURE PLANTS.

families. The lower part (Fig. 7, Sep.) is insignificant. It is composed of five green, toothlike organs, called sepals, connected at their base. The upper part, popularly called the flower, consists of five mostly showy petals. One of these is much larger than the others and encloses them in the bud. It is called the standard (Fig. 7, St.). The lateral ones are irregular in shape and are called wings (Fig. 7, NV.). The two others grow together, forming a boatlike organ called

Fig. 7—Tl.e different parts of a flower of Pea.

Natural size.

W.—Wing.   St.—Stamens.

K.—heel.   0.—Ovary of pistil. P.—Stigma of pistil.

the keel (Fig. 7, K.), which encloses the stamens (Fig. 7, St.) and the pistil. Nine of the ten stamens grow together in their lower parts, forming a tube that encloses the pistil. Each flower has only one pistil. It consists of a broad lower part, the ovary (Fig. 7, O.) and a narrow upper part, strongly knee-bent and developed at its top into a stigma (Fig. 7, P.).

Fertilization: Fertilization in leguminous plants is never per-formed by air currents. In a few genera, such as peas and vetches, the flowers are self-fertilized; that is, the pollen automatically fertilizes the pistil of its own flower. In most leguminous plants, however, the pollen is transported from one flower to another by insects, which visit the blossoms for the nectar stored at their base. When the flowers are large and showy, the standard acts as a sign, announcing to the insect the location of the honey. In other species the comparatively small flowers are very numerous, and are thus visible at a long distance. Still others have insignificant flowers borne close to the ground. Such plants, like Trefoil, grow under taller neighbours, and are therefore more or less hidden. But in

Sep.—Sepals S.—Standard.

Picture

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