Pallaviciniites
The lowermost Upper Devonian fossil Pallaviciniites was for a time the oldest known liverwort until Metzgeriothallus was recovered from earlier Devonian strata.
It had a central axis, and bifurcated at its tips; similar fossils have been found in younger strata through to the Pleistocene. With the exception of its elongated axial conducting cells, the thallus was a single cell thick. It had a serrated margin.
Prior to its discovery, the oldest known liverworts dated to the Lower Carboniferous.
