Cross-pollination
Pollination of a flower by pollen from a different plant of the same species.
Also: outcrossing
In cross-pollination the pollen comes from another plant. The seed then mixes two parents, and the seedlings vary, which helps a species cope with disease and change. Most apples need a different apple variety nearby to set fruit. Plant breeders use cross-pollination on purpose: they move pollen by hand from one chosen parent to another and grow the seed to look for new colours or forms. This is how most new roses, lilies and orchids are made.