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 (non-vascular) 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.