Fossil plants preserved within sidertitic nodules have been known from Europaean and North American Carboniferous coal measures since the early 19th Century. However, only a few of them have been described thoroughly palaeobotanically, mainly in the 19th and early 20th centuries; thus their taxonomy often requires revision. Animal fossils preserved within sidertitic nodules beside plant fossils became a base of the description of many rare new taxa of animals undiscovered in other modes of preservation. Published hitherto works about such preserved fl ora indicate that plants preserved within concretions represent rare taxa, not known in other modes of preservation. The dissimilarities in composition of fl oras preserved in ironstone concretions when compared to those from surrounding sediments likely results from the process of concretion formation which selectively infl uences the preservation of small, delicate plant organs. The most famous fl oras preserved within concretions come from Mazon Creek in the USA and Coseley in Great Britain. These localities were the source of many previously unknown taxa with important evolutionary signifi cance. The new flora preserved within concretions has been discovered recently in Poland in Sosnowiec (Upper Silesia). It contains new, hitherto unknown taxa particularly plant reproductive organs. Comparison of the taxonomy and taphonomy of the ironstone concretion flora from Sosnowiec with other similar assemblages from the Carboniferous of Europe and North America has reveals many similarities steming from a common mode of preservation. Due to the exceptional three-dimensional preservation of the plant fossils, in particular reproductive organs key to the understanding of evolutionary relationships, the locality at Sosnowiec can be regarded as an important new Lagerstätte, and the first such site recognized in Poland. The use of pioneering techniques in high-resolution X-ray microtomography promises to yield yet further information on the biota of this new locality.