Sturia amoena (Stur) Němejc is a Pennsylvanian adpression true fern known from the Charbonnière de Belle et Bonne (Belgium) and from the Radnice and Kladno-Rakovník basins (Czech Republic). This revision includes a detailed study of pinna and pinnule morphology, aphlebiae and reproductive organs. Interesting details of sporangia and in situ spores are described for the first time. The sporangia of Sturia amoena have an equatorial bi-triseriate annulus and yielded in situ spores of the Punctatisporites and Apiculatisporites types.
Milan Libertín, Jiří Kvaček, Jiří Bek and Petr Štorch
Plant mega- and microfossils are described from the middle Sheinwoodian of the Barrandian area. The material comes from the Loděnice locality and the same horizon as the earliest unequivocal land plant, Cooksonia barrandei LIBERTÍN, J.KVAČEK, BEK, ŽÁRSKÝ et ŠTORCH. Its age (432 Myr) is inferred from the associated graptolite fauna, including the zonal index graptolite Monograptus belophorus. Megafossils have clear similarity with Cooksonia, due to their dichotomised axes with slightly widened subtending axes bearing putative sporangia. They document some of the plant diversity that was in place when the first proven representative of the genus Cooksonia appeared, and together with dispersed spores they provide strong and important evidence that a diversified terrestrial ecosystem had developed on the Barrandian volcanic archipelago in the peri-Gondwanan realm by the end of the Sheinwoodian Stage of the Silurian Period.