Vegetatiehistorie van Jardinga (Fr.)
Botanical macro-remains and pollen were studied from a section in one of the trenches in the vicinity of the Tjonger near Jardinga. The section includes the Pleistocene soil and the complete peaty sediment which was deposited during most of the Holocene. The two diagrams resemble each other and indicate that the pollen diagram represents the local vegetation. The vegetation succession of the Late Glacial and the pollen zones of the Holocene are described. Special attention is paid to Slender-Leaved Pondweed (Pota-mogeton filiformis), a submerged water plant indicative of calcareous soils. During the Pleistocene, this species was probably common throughout the country, whereas subfossil remains from the Subatlantic and recent localities are confined to the coastal area. It is assumed that the improvement of the climate, resulting in an increase of precipitation, reduced the influence of seepage with calcium-rich water.