Surprisingly, phytoplanktonic organisms in samples of the Lower Triassic (early Buntsandstein) show high diversities of species of green algae and acritarcha. In the Lower (Calvörde and Bernburg formations) up to the early Middle Buntsandstein (Volpriehausen Formation), phytoplankton species are evenly dominant in several layers characterised by greyish clay- and siltstones. First investigations of this issue were presented by Schön (1967) and extensively by Schulz (1994, unpublished), who both concentrated on samples from NE and E Germany. These results were verified and supplemented for the southern part of the North German Basin in recent studies. Apart from uni- and multi-cellular green algae, a great variety of acritarch taxa (Leiofusa,Metaleiofusa,Deunffia,Veryhachium,Micrhystridium,UnelliumandMultiplicisphaeridium) are recorded. EspeciallyLeiofusa,DeunffiaandVeryhachiumshow aberrant forms, pointing to anomalous environmental conditions and/or water chemistry. Furthermore, often only a few other terrestrial palynomorphs (spores and pollen grains) are found in horizons dominated by phytoplanktonic taxa. Therefore environmental conditions must have been unfavourable for higher plants during sedimentation of the greyish clay-/siltstone beds. Combined with interpretation of the lithological proxies, the results show that sedimentation took place in a mainly terrestrial environment most of the time. Numerous acritarchs support the idea of marine episodes within the Lower and Middle Buntsandstein, especially during the Volpriehausen Formation.