Zs. P. Komáromy szerk.: Studia Botanica Hungarica 14. 1980 (Budapest, 1980)
Szolláth, György: Data to the flora and vegetation of the Gerecse Mountains I.
one west-east directed block trent, Gete is formed by uplifted blocks (Korpás 1933f this is the very subject of our examinations. The geological structure, determining the development of the vegetation, is not unvaried in the least. Its oldest formations are the upper Trias dolomite and Dachstein limestone on dolomite of the same age. Dolomite has varying chemical purity in the Gerecse Mts.; CaCOg is predominant especially in the offset (Korpás 1. c. ). These two bed-rocks strike to the surface at the southern sider of Magos-hegy and Nagy-Gete mixed with one another (Oravecz 1961), (Map 1). This phenomenon makes its effect felt in the rock-vegetation formation. But the main part of Dachstein limestone which appears as huge shoulders e. g. on the uplifted blocks of Hegyes-kő and Kis-kőszikla but they can well be seen on Öreg-kő as well. Dachstein limestone becomes karst easily but here this process takes place only in deeper levels (cave creation). Signs of karrification can be observed on the surface (e. g. Hegyes-kő). As a consequence, there are very few superficial streams, the existing ones are fed by leaking waters drained off by limestone layers, an example is found in a north-south directed alluvial erosive graben of the western part of the area. Younger geological formations are found on the surface and in the dephts as well. The multiply faulted Eocene and Oligocène brown coal beds lay on subsided crust fragments surrounding the blocks on all sides (Korpás I.e.). Hollows between uplifted blocks are filled with Pleistocene loess - in thick layers in some places - which plays an important part this land (Korpás I.e.). The sand also contributed to lend variety to this area; it was spread out by the prevailing NW-SE wind on the northern margin of the Gerecse Mts. (Korpás 1. c. ). Climatologie conditions Based on the data of the Central Meteorological Office (henceforth CMO) as well as data that can be read from maps, the average annual temperature is about 9-10 °C; average of the growth season ^April-September) is 16-17 °C; the average annual change of temperature is between 21, 5-22 C (Bacsó 1948). Average annual rainfall on the area is 550-600 mm; in the growth season 300-350 mm (Hajósy 1952). Data of the meteorological station of Dorog: 576 mm and 322 mm (CMO). It appears from Walter's climate diagrams based on the data of the surrounding meteorological stations (Esztergom, Páty and Dorog) that the climate of the area surrounded by the points of flatlands is semiarid-semihumid, which makes growing of woody steppe vegetation possible (Borhidi 1961). As a consequence - considering the height conditions - the Gete group lay in the zone of Turkey oak (Q uercus cerris ) and - just as the whole Gerecse Mts. - it is of fairly dry character. This is one of the reasons of the relative poorness of the flora here, comparing it with the Vértes, Pills and the Visegrádi Mts. (Boros 1953). An other important conclusion also can be drawn according to the dispersion of the annual rainfall: the rainfall maximum of May, which is characteristic of the south-west wing (Praeillyrico— Matricum, Zólyomi 1942) of the Hungarian Central Mountains, appears here as well (see data of CMO) though indistinctly, coming nearer and nearer to the summer (June-July) rainfall maximum of the temperate zone (Zólyomi I.e.). This maximum of late spring can be considered as the irradiation of the Mediterranean climate (Zólyomi I.e.); it can be seen also in the proportion of flora elements: as in the Vértes so in the Gerecse Mts. . Mediterranean flora elements are present at a relatively high percentage (8%) while in the Visegrádi Mts. - though the difference Is not significant - they can be found at 7% (Boros 1953, Száraz 1976). Soils a) Stony, rocky skeletal soils are to be found on steppe slopes and rock shoulders with pioneer plant communities and open rock-vegetation. b) Rendzina soils of different depths - formed by disintegration at an advanced stage - are the soils of extreme watereconomy of closed rock-vegetation, of slope steppe, of karst scrub-forests and calciphilous oak forests.
