Abstract Non-pollen palynomorphs (NPPs) are ‘extra’ microfossils often found in palynology slides. These include remains of organisms within the size range of pollen grains ( c. 10–250 µm), resistant to laboratory treatments used for the preparation of palynological samples. NPPs are a large and taxonomically heterogeneous group of remains of organisms living in diverse environments. Taxonomically, they belong to a wide variety of groups such as cyanobacteria, algae, vascular plants, invertebrates and fungi. The aim of this chapter is to provide a general overview of NPP groups observed in palynology slides. It includes more than 40 of the most common groups starting with acritarcha, cyanobacteria and algae, moving through transitional groups to animals and fungi and finishing with human-made objects such as textile fibres. Although far from complete, it provides an updated overview of taxonomical diversity of NPPs and their indicator values. Further works on NPP identifications are of great importance to improve our current knowledge. Since NPPs occur in all kinds of sediments, their analysis is a powerful tool for reconstructing environmental changes over time. Further detailed studies of specific NPP groups and their indicator values will open the way for new fields of study.

We have identified a total of 56 chrysophycean stomatocyst morphotypes from the postglacial sediments of Elk Lake, Minnesota. Cysts were well preserved and abundant throughout the lake’s history. Stratigraphic changes in the 22 dominant cysts were correlated with other paleoecological information available for this core. In general, shifts in chrysophyte assemblages coincided with inferred changes in past climate. The most striking change in chrysophytes occurred about 8.5 ka, and coincided with the shift to prairie-vegetation dominance in the lake’s drainage basin. The relative proportion of chrysophycean stomatocysts to diatom frustules also decreased at that time. A second major shift occurred about 5.3 ka, with the return of a chrysophyte assemblage resembling, in some respects, the early postglacial flora. Stratigraphic analyses at decade resolution recorded more recent changes in cyst assemblages that presumably track climatic variables. The relative abundance of chrysophytes appeared to be exceptionally high (values of about 40%–80%) during the Little Ice Age.