Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 90. (Budapest 1998)

Medzihradszky, Zs. ; Bajzáth, J.: The occurrence of arctic-alpine Betula species in the Hungarian Pleistocene

RESULTS OF POLLEN ANALYSIS Morphological investigations and size measurements of Betula pollen were carried out in order to separate the pollen of Betula nana from the Betula alba type. The results unambiguously verified the presence of Betula nana pollen in accordance to the macrofossil analysis. Methods. The sample was prepared by HCl. KOH, acetolysis, HF and it was mounted in glycerine. A Nikon microscope with 10 x oculars and 60 x oil immersion objective was used for the morphological identification and a 100 x oil immersion objective for the measurements. The grain diameter in polar view (Lt) and the pore depth (P-alt) of 104 Betula pollen grains were measured to the nearest ocular line (one line = 0.96u.). Pollen morphological analysis. Each grain was attributed to either Betula nana or Betula alba type. The identification of Betula nana pollen was made according to the general pollen morphology criteria given by TERASMAE (1951), ERDTMAN et al. (1961), PRAGLOWSKI (1962) and GAILLARD (1983). For Betula nana type, the shape of the grain is.rounded in polar view, the pores are rounded and slightly extruding, the pore annulus is narrow, and the exine is thin (Fig. 2). The Betula alba type differs from B. nana type by the more triangular shape of the grain in polar view; more or less rectangular pores, that are distinctly extruding; its larger pore annulus, and thicker exine. The morphological analysis clearly showed that there are two different types of Betula pollen grains in the studied material. Number of pollen grains Fig. 10. Distribution of Lt/P-alt ratio of the Betula pollen (Győr, Szabadrét-domb)