L. Hably szerk.: Studia Botanica Hungarica 22. 1990 (Budapest, 1990)

FLORISTICAL EVALUATION Evaluating any of the floristical assemblages we are facing the problem of the distorting effect of fossilization on the complete flora. Our fossil floristical assemblages are, at the very best, taphocoenoses

, including those plants mainly that were nearer to the place of fossilization

, or their transport to the place was rendered possible by some media. Estimating the extent of selection would be tentative, as we have no direct proofs on this fact. Perhaps nearest to the truth, we can adopt the principle 'many out of many, few out of few'. Therefore we cannot neglect the individual number when evaluating the assemblages. For an adequate separation of the taphocoenosis according to biocoenoses we should be aware of the ecological requirement of the very species, whereas we are confined here to hypotheses on morphological basis as well as the principle of actualispi. This principle can be applied already with acceptable certitude to Tertiary floristical assemblages; however, in many cases it is difficult t'o judge, which is the recent equivalent of a given fossil species, or, define its nearest relatives. If we cannot do this, we have to face the possibility of another source of error considering

, in general, the ecological demands of a genus or a family. Still there are certain genera or even families which are very consistent and unified concerning their ecological requirements , therefore even a loose determination of the members is enough without making great errors or ecological inconsistencies in our deductions. There are 48 species present in our fossil flora, assigned to 20 families. In respect of individual number, there are members of the families Lauraceae, Taxodiaceae, Platanaceae and Ulmaceae present in the greatest quantity. #

Wnile the Lauraceae are represented by many species of several genera in the assemblage, Taxqdiaceae and Ulmaceae are represented by two species each, Platanaceae by a single species only. The number of Arctotertiary species, or rather, genera is higher than in other Hungarian floras of the Egerian period Verőcemaros (HABLY 1982), Kesztölc (HABLY 1988), Nagysáp (HABLY 1989), but in respect of individual number, it is only the species Ulmus pyramidalis playing a more important role among them within the assemblage. The family of Betulaceae is present with various forms having, however, only one specimens of each here. The same can be stated concerning the rest of the Arctotertiary element in the flora. The bulk of the flora was composed of, correspondingly, the Palaeotropical elements. The high diversity and great individual number of the family of Lauraceae is undoubtedly testifying that the genus was in its prime during the Egerian Stage. The same can be said about the Platanus neptuni as well. Consequently, the flora was dominated by thermophylous elements supported by the presence of palm trees as well. From the point of a floristical evaluation it is remarkable that Palaeocarya orsbergensis is missing from the assemblage, a species which is generally spread in great quantities within the Egerian floras of Hungary. We have to mention the presence of the family of Leguminosae here, represented by several leaf forms, and fruits, similar to other Egerian floras in Hungary, thus it can be regarded as a characteristic member of the assemblage. From the point of floristical composition, the'presence and diversity of the family of Betulaceae should be stressed as the major difference in respect of the other Egerian assemblages of Hungary, as well as the presence of Acer angustilobum and the high individual number of the representatives of the Taxodiaceae family. THE PHYT0C0EN0SES OF THE VÉRTESSZŐLÖS FLORA AND THE PALAEOGEOGRAPHICAL RECONSTRUCTION The dominant species in our assemblage are of fairly different ecological requirements. The differences existing between their ecological demands should be explained, first of all, not by climatological

, much rather, eda-