CHAPTER LX.
1167. Why do some plants droop, and turn to the earth after sunset?
Because, when the warmth of the son's rays is withdrawn, they turn downwards, and receive the warmth of the earth by radiation.
1167. Why does the young ear of corn first appear enfolded in two green leaves?
Because the light and air would act too powerfully for the young ear; two leaves therefore join, and embrace the ear, and protect it until it has acquired strength, when they divide, and leave the ear to swell and ripen.
1168. Why are the seeds of plants usually formed within the corollas of flowers?
Because the petals of the flowers, surrounding the seeds, afford them protection until they are ripened, when the flower dies, and the petals fall to the ground.
1169. Why does the flower of the poppy turn down during the early formation of seed?
Because the heat would probably be too great for the seed in its early stage. The plant is therefore provided with a curious curve in its stalk, which turns the flower downward. But when the seeds are prepared for ripening, the stalk erects itself, and the seeds are then presented to the ripening influences of the sun.
1170. Why have plants of the pea tribe, a folding blossom called the "boat," or "keel?"