Protosalvinia

Protosalvinia ("early Salvinia") is a prehistoric plant found in shale from the shoreline habitats of the Devonian Period.

Description
It is not currently known what type of plant Protosalvinia is. A possible interpretation is that it is a type of liverwort or brown alga, although no specimens of brown algae are confirmed to have existed in the Paleozoic and the fossils share no features common with modern brown algae.

Living examples of Protosalvinia were thalli with short dichotomous branching. The branches of the largest species were up to one centimeter across. Protosalvinia had spores which were produced by meiosis.

Classification
The name Protosalvinia is misleading. The name literally means "early Salvinia", and was given because it was believed that the fossils were an earlier form of the living aquatic fern Salvinia. It is no longer believed that the fossils come from a fern, but their true identity is still as of yet unknown.

There are four different species of Protosalvinia, and one synonym, Foerstia.