Plants were not understood to require a male reproductive contribution analogous to animal fertilization.

Flowers clearly contain specialized structures, but their reproductive roles were not obvious before modern botany.

Pollen in particular had several proposed explanations. It could be treated as an excretion, a nutrient, or simply another plant substance rather than as part of a male reproductive system.

Rudolf Jakob Camerarius provided an important experimental test in the seventeenth century.

He removed or isolated the pollen-producing structures of plants and compared what happened to seed production. In his 1694 work, fertile seeds depended on access to pollen.

Later microscopy clarified what pollen actually carries.

In seed plants, a pollen grain contains the male gametophyte, the small reproductive generation that eventually produces sperm cells. After pollination, a pollen tube can grow toward the ovule and deliver sperm. Fertilization occurs when a sperm cell fuses with an egg cell, producing the embryo of the next generation.

Plant reproduction is more varied than the familiar animal pattern. Many flowers contain both male and female reproductive structures, some species separate them among different flowers or individual plants, and many plants can also reproduce asexually.

The important correction is that sexual reproduction is a fundamental part of plant biology, even though plants carry it out in their own distinctive way.