The Evolution of Plants

On land, the world used to be dominated by the simple non-seed plants, including Horsetails and Ferns, which reproduced by the use of spores.

When plants first came onto dry land, seed-plants, like pine and oak, did not exist.

The seed-plants developed after more simple plants had already become established on land. This makes sense when you think that the reproduction of seed-plants involves pollination by pollen grains which are dispersed through the air, and so are highly adapted for life on land.
It took time for this ability to evolve.

After the simple plants, it was the turn of the primitive seed-plants to take over. These were the "Gymnosperms", such as firs and pines. The use of seeds probably developed from spore-bearing plants with woody tissue, like the ancestors of ferns.

Later, the more complex seed-plants - the "Flowering Plants", took over. Some water plants, like lilies, are complex flowering plants that produce pollen. It is thought that these evolved from land plants that returned to the water. Today, the world is still dominated by the flowering plants, including trees, flowers and grasses - also known as "Angiosperms".