First anatomical description of silicified calamitalean stems from the upper Carboniferous of the Bohemian Massif (Nová Paka and Rakovník areas, Czech Republic)

Silicified stems are very abundant in the upper Palaeozoic basins of the Czech Republic. The results of an anatomical study of the silicified calamitalean stems from the KrkonoÅ¡e Piedmont and Kladno-Rakovník basins are presented here for the first time. In the KrkonoÅ¡e Piedmont Basin, there are various silicified plant remains, but the presence of calamitalean wood is restricted to only one stratigraphic unit, to the so-called “Ploužnice Horizon”. Only a few data on the systematics of permineralised or petrified stems from the Kladno-Rakovník Basin are available, anatomical descriptions are largely lacking and fossilised calamitalean stems were unknown. The fossils can be attributed to two species: the common Arthropitys cf. bistriata and the rare Calamitea striata; the occurrence of the latter is limited to the KrkonoÅ¡e Piedmont Basin.