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Petrified woods from the Kyffhäuser (Siebigerode Fm., Saale Basin) are among Germany's most voluminous occurrences of petrified trees. We reconstruct the provenance and fossilisation of the silicified logs and accompanying fossil plants based on sediment architectures documented in 15 quarries, plant-anatomical analyses of 112 specimens from eight collections and cathodoluminescence microscopy of silicified tissues. The up to 20 m long Agathoxylon trunks derived from 40 m tall cordaitaleans and conifers. Alluvial processes, the erosion of adjacent basement slopes during floods and storms were the main forces to recruit large woody debris from seasonally dry forests growing in extrabasinal habitats. A climatically controlled high discharge variability and the large-scaled, low-sinuous channel geometry ensured transport of the trunks across a 60 km distance towards the basin centre. Deposition of the logs occurred during the waning flood stage accompanied by the formation of four large woody debris-induced sedimentary structures. The stratigraphic occurrence of silicified trunks indicates a hydrodynamic window of log entombment constrained by river morphology, discharge regime, wood shape, and wood density. The synsedimentary to early postsedimentary silicification was a millennium-scale twophase process and resulted in selective tissue preservation referred to as "pointstone". Imprints from associated floodplain deposits reveal sparse riparian vegetation consisting of ferns, calamitaleans, pteridosperms, and juvenile to shrub-like cordaitaleans. Results demonstrate the potential of multidisciplinary approaches in interpreting plant taphocoenoses and highlight the Kyffhäuser as a crucial locality to elucidate late Palaeozoic vegetation dynamics. [ABSTRACT FROM AUTHOR]

The first plant assemblage of the Upper Muschelkalk from Bruchsal was recovered from a single horizon of the basal Trochitenkalk Formation (late Anisian). The mono-dominated plant assemblage is dominated by vegetative and reproductive organs of conifers, associated with few dispersed root fragments and a female cycad scale. The fragmentary nature of the plant assemblage is ascribed to the transport from terrestrial growth environments and re-deposition in the Upper Muschelkalk Sea at its early transgressive stage. Both factors contributed to the reduction of more delicate, hygrophytic elements and concentration of coriaceous structures, and thus resulted in a taphonomic bias that substantially altered the fossil record. The mono-dominated assemblage is the result of a combination of xerophytic regional flora, arid to sub-arid palaeoclimatic conditions, and a taphonomic bias based on a long transport of the macroremains. Nonetheless, the Bruchsal plant assemblage is much more abundant and diverse than any previously described assemblage from the Muschelkalk. [ABSTRACT FROM AUTHOR]