B. Papp szerk.: Studia Botanica Hungarica 32. 2001 (Budapest, 2001)

Hably, Lilla: Rhamnus warthae Heer, an important element of the Central Paratethyan region during the Egerian

more or less continuously close to the sedimentary basin. Their presence is more or less autochthonous, and refers to a swampy, partly riparian vegetation. The leaves of "Rhamnus" warthae are variable, but the large and wide leaves are dominant and typical. Most of the leaves of various species collected here, are usually large, like those of Alnus oligocaenica Andr., Ulmuspseudopyramidalis Z. Kvacek et Hably, "Talauma" egerensis Andr., Tetracentron agriense (Andr.) Z. Kvacek et Hably, Acer tricuspidatum Bronn f. hungaricum (Andr.) Z. Kvacek et Hably. At the other important locality of "Rhamnus" warthae, namely in the Zsil Valley, we find similar conditions (STAUB 1887, GlVULESCU 1973, KVACEK and HABLY 1991) as in the Eger-Wind brickyard. At all other localities, where "Rhamnus" warthae have been occurred: Kesztölc (HABLY 1988), Nagysáp (HABLY 1989), Andornaktálya (HABLY 1993a), Pomáz (HABLY 1994), swamp vegetation is very subordinate. In these localities only a few leaves of this species were recorded, even from the rich, well preserved floras (e.g. Pomáz). The above data and observations provide sufficient support for our conclusion, that depending on the edaphic factors "Rhamnus" warthae was part of a swamp vegetation. DISTRIBUTION OF "RHAMNUS" WARTHAE HEER The palaeogeographical distribution of this species is limited to the Central Paratethyan area, more closely to the Intra-Carpathian region, e.g. Hungary and Transylvania. No data of this species is known out of this region. All the floras, containing the species, are dated from the Egerian (Upper Oligocène) age. All above facts suggest, that it was an endemic species. The appearance of "Rhamnus" warthae Heer correlates with the abrupt floral change at the boundary of the early and the late Oligocène (HABLY 1993b). At that time a great number of species became extinct, however, several of them have successfully passed this time frame, although their abundance might have decreased or unchanged. After this boundary some of them showed increased abundance, and have become more important than before. There is a group of species, which appeared firstly in the Egerian, and included the first representatives of the "Arctotertiary" elements as well as several thermophilous elements like "Rhamnus" warthae Heer. The large-scale turnover of the vegetation was much more complex than it could be explained solely by cooling of the climate. Geological events affecting terrestrial vegetation by changing significantly the environment and cli-