Seed plants have special structures on them where male and female cells join together through a process called fertilisation.
After fertilisation, a tiny plant called an embryo is formed inside a seed. The seed protects the embryo and stores food for it. The parent plant disperses or releases the seed. If the seed lands where the conditions are right, the embryo germinates and grows into a new plant.
Scientists divide seed plants into two main groups: plants with flowers and plants with cones. They also have special names for these groups. Plants that have flowers are called angiosperms. Plants that hold their seeds in cones are called gymnosperms.
Angiosperms have flowers. The flowers are special structures for reproduction. They contain male parts that make pollen and female parts that contain ovules. Some plants have these male and female parts in different flowers.
Pollen is carried from a male part to a female part by wind, insects or other animals (a process called pollination), where it releases male gametes that fertilise the female gametes in the ovules. The ovules develop into seeds from which new plants will grow.
Gymnosperms are seed plants but their seeds are held in cones. Male cones make pollen, which is carried to female cones by the wind. After the female gametes are fertilised by male gametes from the pollen, the female cones produce seeds, which are then scattered away from the plant by wind or animals.
Learn more about plant reproduction from ScienceLearn.org.nz.
For further reading, see Britannica.com's plant reproductive system.