B. Papp szerk.: Studia Botanica Hungarica 38. 2007 (Budapest, 2007)

Szollát, György, Seregélyes, Tibor, S. Csomós, Ágnes; Standovár, Tibor: The flora and vegetation of Gödi Láprét near Göd, Pest county, Hungary

later. Various semi-consolidated forms of sand dunes, like blowouts, yardangs, longitudinal dunes, characteristic of the Duna-Tisza köze (Danube-Tisza Interfluve region) and also of the Szentendre Island, can also be recognised in the survey area, although to a lesser extent (PÉCSI et al. 1958, KARÁTSON 1997, Botanikus Bt. et al. 1998). The deeper parts of the Gödi Láprét developed most likely by filling-up with alluvial deposits to the former riverbed or dead-arm of the Danube. The different soil types have developed in correlation of the local geomorphological features. In deeper areas where the water-table is close to the surface, fen soils, meadow soils have developed while different sandy soils are characteristic in the dryer areas (MOLNÁR and SZABÓ 1998). The Ilka stream and a thermal water ditch cross the northern part of the survey area, both running in controlled channels. Their water, as well as the runoff and the undersurface water move westward to the Danube. The study area is part of the Great Hungarian Plain not only geographically, but also in terms of its phytogeography: it belongs to the Praematricum (Duna-Tisza köze) floristical district of the Eupannonicum (Great Hungarian Plain) floristical region (Soó 1964, PÓCS 1981). METHODS OF SURVEY As it was mentioned in the Introduction, the systematic investigation of the area began in 1992. Some of the botanical values of the area have already been known previously, but we could not find previously recorded data on the vegetation of the surveyed area. The vegetation map and the species list were completed during many days of fieldwork in 1992, and the vegetation types have been characterised by general descriptions in a report by SZOLLÁT et al. (1992). In 1998 all distinct patches of vegetation (marked by serial numbers) were individually characterised, with special emphasis on the changes that occurred in the composition of the flora and the vegetation since 1992. The descriptions of the vegetation patches are completed with their respective species lists, and with the estimated population size of the protected plants (SZOLLÁT 1999, 2000). (The data of the estimated population size of Carex davalliana, Iris sibirica, Schoenus nigricans, Stipa borysthenica refers to the clumps of these species). The relative number of the protected plants occurring in the entire area have increased several times since 1992 - with one reason being the legislative revisions and adjustments that occurred for nature conservation in 1993 and 2001. Also, as a result of new findings realised within the area, partly by Ádám Selmeczi Kovács in 1997 {ex verb. ) a number of protected plants have been added to the already existing lists. While some of these newly recorded species have simply escaped our notice before, others could have appeared in the area while the research period, or their population have gone up from a few specimens in 1992 to a more noticeable number later on. Subsequent changes in the naturalness of the vegetation have been monitored by regular observations since 1998. In the nomenclature of the species we used FLÓRA database 1.2 (HORVÁTH et al. 1995), except in a few cases when we followed SIMON (2000). Other exceptions include the spelling of sadleriana, or the taxa of Molinia: for these we accept the taxonomy of