Page:First course in biology (IA firstcourseinbio00bailrich).pdf/186

 , with string inserted.

The fig is a hollow torus with flowers borne on the inside, and pollinated by insects that enter at the apex.

the time for pollination has come. If the bag is slightly moistened, it can be puckered more tightly about the stem of the plant. The time required for the stigma to mature varies from several hours to a few days. (c) When the stigma is ready, an unopened anther from the desired flower is crushed on the finger nail or a knife blade,and the pollen is rubbed on the stigma by means of a tiny brush, the point of a knife blade,or a sliver of wood. The flower is again covered with the bag, which is allowed to remain for several days until all danger of other pollination is past. Care must be taken completely to cover the stigmatic surface with pollen, if possible. The seeds produced by a crossed flower produce hybrids, or plants having parents belonging to different varieties or species. 165. One of the means of securing new forms of plants is by making hybrids. Why?