L. Lőkös szerk.: Studia Botanica Hungarica 26. 1995 (Budapest, 1995)

Penksza, Károly: Flora of the Őr-hegy (Gerecse Mts, Hungary)

(Thunbg.) Fr. also occurs sporadically on the steeper western and southern slopes covered by shrub forest associations. In 1986 a specimen of Asplenium adiantum-nigrum L. was found on the steep eastern slope of the Őr-hegy. Its occurrence was probably due to the acidic soil formed locally on a sandstone spot upon the limestone. Although this species could be a new data for the mountains unfortunately neither this nor other specimens have not been found since 1986. A very interesting new data is the occurrence of Acer tataricum L. (PENKSZA 1991) on the western slope and on the ridge of the hill. It was presumably more widespread on the hill before the deforestation, and it is probable that the Aceri tatarico-Quercetum association was also common in the Gerecse Mts. This site is an additional new one to the area of the species presented by ZÓLYOMI (1957) and ZÓLYOMI and FEKETE (1994). Among the so-called loess species two major populations of Phlomis tuberosa L. can be found, one of them surprisingly right on the top, proving that the hill must have been covered by loess. Other characteristic loess species like Taraxacum serotinum (W. et K.) Poir. and Cytisus austriacus L. occur in large numbers. In the most xerophytic rocky grasslands of the Őr-hegy, Festuca valesiaca Schleich, replaces Festuca pallens Host. Among xerophytic grasses Festuca rupicola Heuff. does not grow anywhere, as it occurs always in more mesophytic grasslands at lower temperature. This consequence can also be drawn from the investigations of the rocky grasslands on the Fehér-szirt near Kesztölc (PENKSZA 1993). Figure 2 shows the range of some protected and rare species of the area. Figure 3 shows the evaluation of nature conservation ranks of the species of the Őr-hegy. Species occurring near arable lands - mainly weeds - are omitted. The figure indicates that the Őr-hegy is an area of high botanical value, it should definitely be protected, being rich in species although its area is quite small. Acknowledgements. I am grateful to Béla Dános and András Horánszky for giving me the opportunity to study this area and for revising my identifications of vascular plants. Thanks are due to Miklós Rajczy for the identification of moss species. Studio bot. hung. 26. 1995