Flowers of plants can be divided into bisexual flowers and unisexual flowers. Androgyny refers to a flower with both stamens and pistils. A unisexual flower refers to a flower with only pistils or stamens. Among unisexual flowers, only stamens are called male flowers, and only pistils are called female flowers. Some male flowers and female flowers bloom on a single plant, which is called dioecious, such as ginkgo biloba and so on. Some plants have both male and female flowers, which are called monoecious plants, such as cucumbers. Monoecious plants need another male flower pollen and female flowers to complete pollination and fertilization, which is called cross-pollination.