Insects go from flower to flower for nectar which they make into honey, and also for pollen, which they use as food. As an insect collects pollen from a flower (there is always more pollen than the plant needs), some of it rubs off on the insect's body. Then, when the insect visits another flower, some of the pollen rubs off onto the stigma. Thus the insect helps the plant while it is helping itself.
Cross-Pollination and Close-Pollination Transfer of pollen from one flower to an- a: other is called cross-pollination, in contrast to close or self-pollination. Close-pollination is the transfer from anther to stigma of the same flower. Both close-pollination and cross-pollination may occur in the same flower.
No seed is produced, however, if pollen from one plant is transferred to an entirely different kind of plant. A mature pollen tube is not produced. Pollen from a grass plant blown onto the stigma of an apple flower would not help form an apple seed.