B. Papp szerk.: Studia Botanica Hungarica 36. 2005 (Budapest, 2005)

Szollát, György; Standovár, Tibor: Botanical values of the Öreg-hegy and Juhász-halom near Csomád

The narrow northeast-facing side of the valley is covered by a mosaic of relatively dense shrubby vegetation with some patches of Robinia pseudo-acacia and seriously degraded grassland patches. However, there are also some smaller patches of intermediately degraded grasslands. Under the dense groups of shrubs formed by Crataegus monogyna herb layer is composed of nitrophytes (Bromus sterilis, Alliaria petiolata, Galium aparine). In the meadow-steppe patches Festuca rupicola is the dominant species, with Chrysopogon gryllus and Stipa capillata in a few less disturbed patches. Poa angustifolia, Botriochloa ischaemum and the large patch-forming Bromus inermis are also typical. The dominance of monocotyledons is supported by the presence of Agrostis stolonifera subsp. gigantea, Phleum phleoides, Koeleria cristata, Agropyron repens. On this side of the valley there are more generalists and disturbance tolérants than on the other. Except for the hundreds of Colchicum arenarium, protected plants are represented by only the few Astragalus excapus and Vinca herbacea individuals. The opposite (southwest-facing) wider side of the valley is mostly covered by intermediately degraded grasslands, turning to seriously degraded shrubby (Crataegus monogyna) grasslands toward the bottom. However, some semi-natural species rich patches survived, mostly on sandstone bedrock. Stipa capillata, Chrysopogon gryllus, Botriochloa ischaemum, Festuca rupicola, F. pseudovina are the typical dominants. In slightly more degraded patches Festuca rupicola and Poa angustifolia, whereas in seriously degraded ones Agropyron repens, Poa angustifolia, Cynodon dactylon, Bromus inermis predominate. Trifolium arvense, Apera spica-venti, Teucrium chamaedrys and Rumex acetosella typically grow on recently disturbed sites. Emphasis should be put on the occurrence of the protected Linum tenuifolium on a sandstone exposure (PÁNDI, I., ex verb.). Adjoining to the area from the south, there is a smaller, somewhat degraded patch of calciphile sand steppe. In its less dirturbed parts Stipa borysthenica is dominant, Festuca vaginata, Astragalus excapus and Helichrysum arenarium also occur, while Orchis morio and Festuca x wagneri only found at this location. (The protected plant species occurring in the Juhász-halom are listed in Table 1). CONCLUSIONS Vegetation of the Öreg-hegy and Juhász-halom deserves attention for several reasons. As it was mentioned in the Introduction, this area belongs to one of the largest continuous relic of semi-natural vegetation between Budapest and Vác. Vegetation is rather rich in rare species. By now we have found 33 locally or regionally rare species most of them are protected by law. These 31 protected plant