Variability and stratigraphy of the tussocks of Carex Apropinquata Schum

Abstract

Thirty tussocks of Carex appropinquata Schum. from various parts of the peatlands in the Biebrza River valley were analysed. The results confirmed the variability of the shape in tussocks and a considerable range of their height (15-34 cm). The group of tussocks from the vicinity of the river Kosódka was higher (usually exceeding 25 cm) and had a characteristic pole-like shape. The shape of the tussock and especially the slope of its sides determine to a high degree the possibility of development of other species growing on the tussocks. Two different parts can be distinguished in the structure of the tussock. The outer layer (of ash content on average 6,5%) is built mainly of leaf sheaths of Carex appropinquata and numerous roots of other species growing on the tussocks. The inner layer consists mainly of thick roots of the sedge and few fine roots of other species. The ash content in that layer ranges from a dozen or so to as much as 26%. The number of Carex appropinquata nuts varies between layers of the tussock and between tussocks, and decreases towards the basis of the tussock. The number of nuts may to some degree characterize the fertility of individual plants, and changes in fertility of the same individual over a period of several dozen years.