The fruit is a pod (Fig. 3), which opens when ripe along both margins and liberates the seeds. Laburnum seeds are poisonous, but the seeds of many other plants of the family (peas, beans, lentils, etc.) are valuable foods. 19. THE ROSE FAMILY. 1. The wild rose (Fig. 75).—With a sharp knife cut vertically through the middle of a wild rose. Notice that the receptacle forms a deep cup, and that the carpels of the pistil are enclosed in the cup. From the edge of the cup spring the five sepals, five petals, and numerous stamens. What is the great difference between a rose and a buttercup? Trace the formation of the succulent fruit or hip from the receptacle cup of the flower. Cut through a rose hip, and observe the ripened carpels in the interior. 2. The blackberry.—Similarly examine a blackberry flower (Fig. 76). This is still more like a buttercup, but—as in the rose and the pea—the calyx, corolla, and stamens seem to spring from a common base, and not to be inserted separately on the receptacle. Trace the formation of the compound fruit, and notice that each part is like a little plum or cherry. 3. The cherry.—Similarly examine cherry blossom (Fig. 77). The pistil consists of one carpel, and is fixed at the bottom of the receptacle-cup, while the calyx, corolla, and stamens are fixed on the margin of the cup. Trace the origin of each part of the fruit. Compare the plum and apricot. [Pg 104] Fig. 74.—Apple Blossom. (× ⅓.) Fig. 75.—Wild Rose. (× ⅓.) 4. The apple and pear.—Cut vertically through an apple blossom (Fig. 74) or pear blossom (Fig. 78), and notice that the ovary is embedded in the receptacle, and that calyx, corolla, and stamens are fixed on the top of this. Cut across the ovary and see the five divisions (carpels). The eatable part of the fruit is the swollen receptacle. Compare the hawthorn. The wild rose.—The plants of the rose family are, most commonly, woody trees or shrubs. The leaves are provided with stipules in nearly all cases. The wild rose (Fig. 75) may be taken as a type of the group. It bears a superficial resemblance to a buttercup, but on dissection considerable difference in the arrangement of the parts is seen. In the rose, the receptacle is urn-shaped; from the margin of the urn spring the five sepals, five petals, and numerous [Pg 105] stamens; while inside the urn the separate carpels of the pistil are inserted. In the blackberry (Fig. 76), raspberry, and strawberry the receptacle is knob-shaped, and the carpels are arranged on the outside of the knob, somewhat as in the buttercup. Here again, however, the calyx, corolla, and stamens differ from those of the buttercup in seeming to arise from a common base. Fig. 76.—Blackberry. 1, flowering branch (× ⅓); 2, longitudinal section of flower (× 1); 3, fruit (× ⅓); 4, diagram of flower. Fig. 77.—Cherry. 1, flowering branch (× ⅔);