Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 83. (Budapest 1991)

Fischer, O. ; Hably, L.: Pliocene flora from the alginite at Gérce

is in the Caucasus, Asia Minor, while some of them, like Populus tremula are also found in Eastern Europe. The species tolerate temperature below zero, however, they prefer warm weather. On the basis of the above-mentioned aspects zonal climate could be a warm-temperate climate. The quantity of preccipitation misht be average and its dispersion changed according to the seasons. The stratification of alginite refers to the unequal dispersion of rain, however, no detailed examination has been made in this direction yet. THE SIMILARITY OF SOME MIDDLE-EUROPAN PLIOCENE LOCALITIES BY CLUSTER ANALYSIS With the help of a computer, using the Jaccard's index of similarity in a cluster analysis, the dendrogram (Fig. 3) shows, that Gérce is highly similar with Dománszki Wicrch (ZASTAWNIAK 1972) but this similarity is very low. Real similarity we can found at the next localities: 1. Gerstungcn - Kranichfeld (Germany, MAI & WALTHER 1988); 2 Kemenesmihályfa (Hungary, HORVÁTH E. 1963); 3. Hegyhátszentpéter - Szeleste (Hungary, HORVÁTH E. 1971-72). Rippersroda (Germany, MAI & WALTHER 1988) joins to the 1st group witch much lower similarity, as well as Olaszfa (Hungary, HORVÁTH E. 1971-72) joins to the 3rd group in the some way. At last, the 2nd and 3rd groups are joined at a low simirarity value. It means, that almost all Pliocene florae from West Hungary are more or less similar to each other, expect Gérce, wich differs from the above-mentioned localities. In Fig. 4 we can see the dendrogram of cluster analysis of a matrix of Czekanovski's similarity index. In this case we used not only the species numbers, but the specimen as well. All groups (1, 2, 3,) we can found in the dendrogram too, only join at a lower similarity value. Gérce is not among them, it is joined with Berga (Germany, MAI & WALTHER 1988), and Ruszov (HUMMEL 1983) with a very low similarity. These low similarity values originate partly from the low number of specimens. However, it is quite clear, that the flora of Gérce is very different from the other Hungarian Pliocene florae, and shows closer similarity with some other Middle European localities. The reason of this is the earlier published Pliocene florae belonging to the riparian vegetation, while the flora of Gérce is a remain of a mixed-mesophytic fores. References BERGER, W. (1950): Ein paläobotanischer Beitrag zur Deutung des Pannons im Wiener Becken. - Sitzber. Ost AL Wiss., matk-nat Kl. 159 (1-5): 65-74. BERGER, W. (1952): Die altpliozäne Flora der Congerienschichten von Brunn-Vösendorf bei Wien. -Palaeontogr. 5 92: 79-121. BERGER, W. & Zabusch, F. (1953): Die obermiozäne (sarmatische) Flora der Türkenschanze in Wien. - Neues Jb. GeoL Paläont. Abh. 98: 226-276. BRAUN, A. (1845): Die Tertiär-Flora von Öhningen. - Neues Jb. Miner. GeoL PaL: 164-173. BÔZEK, C. (1971): Tertiary flora from the Northern Part of the Petipsy Area (North-Bohemian Basin). Rozpraxy. 36: 3-118. GAUDIN, CH. TH. & STROZZI, C. (1859): Contributions à la flore fossile italienne II. Val d'Arno. - N. Denkschr. Ges. Naturw. 17:1-59. GÖPPERT, H. R. (1852): Beiträge zur Tertiärflora Schlesiens. - Palaeontogr. B 2: 260-282.