Fossils from 432m years ago push back the origin of the alternating life cycle still seen in ferns today
Our world today is dominated by the flowering plants, or angiosperms, which appeared approximately 130m years ago and rapidly diversified to become the top dogs in most ecosystems. But there are plenty of other plants from more ancient lineages still around, doing deeply weird things in their life cycles, and doing them for much longer than we have realised.
Flowering plants themselves are a refinement of a much earlier innovation about 375m years ago: the seed. Seeds provide protection and a source of nutrition for the embryo, and a handy means of dispersal. A seed germinates and then grows into another plant which is more or less the same as its parents. This is not how spore-producing plants like ferns do things.