-Phytosociological characteristics of grassland communities above serpentines (order Halacsyetalia sendtneri H. Ritter-Studni~ka 1970) in Serbia, are analyzed according to Braun-Blanquet methodology. In order to detect the basic floristic differentiation of analyzed communities ordinary correspondence analysis was applied. Cluster analysis was also performed to see the structure and separation of the communities based on the floristic composition. In order to determine diagnostic species, fidelity indices with presence/ absence data and the size of all groups standardized to equal size were calculated. The new association Stipetum novakii is described in open rocky serpentine grasslands in Brdjani Gorge.

The paper propose nine new nomenclature combinations and indicate eight new synonyms. There are 12 taxa (species and subspecies) of vascular flora which are new for the flora of Serbia (of which nine are autochthonous and three 88 N iketić, M. etal. : Annotated Checklist of Vascular Flora of Serbia II allochtonous plants). An old or unreliable literature records for three autochthonous and one allochthonous plant in the flora of Serbia has been confirmed. Eight plant taxa are a novelty for proper Serbia, Vojvodina, or Kosovo and Metohija, and for three plants, presence in certain administrative units in Serbia has been proved. The last part of the paper contains information on eight taxa whose presence in Serbia or in its territorial units has been refuted.

Monitoring the presence of invasive species in natural wetlands is crucial for numerous reasons, including their negative impact on biodiversity, conservation and the ecosystem services provided by these important fragile areas. The aim of this paper was to investigate the presence and distribution of the highly invasive liana Echinocystis lobata (wild cucumber), and to determine its coenological relations with the native plant species in the Ramsar sites of the southern part of the Pannonian Plain (the southeastern part of Central Europe, northern Serbia). We conducted the phytocenological research of the selected protected riparian areas in detail over a six-year period (2011-2015 and 2020). This study revealed the significant presence of the highly invasive species E. lobata in the studied sites. Wild cucumbers were found in 146 plots in four out of the seven investigated areas. Cluster analyses distinguished four groups of relev?s dominated by E. lobata, which were described, and their dominant and constant species were identified. Habitat type identification was done, and the habitat preferences of E. lobata were determined. The spatial distribution of the four groups is such that they occur in a number of different habitat types or local communities. The species pool which makes up each of these four groups is thus geographically larger than the local community under study, so we can treat them as independently established and well-defined new community assemblages. Plant communities dominated by the invasive species E. lobata have not been described previously. Therefore, this work provides new data, and contributes to the further research and comparative analyses needed to describe invasive plant communities dominated by wild cucumber. In addition, the identification of habitat types which are most occupied by E. lobata is very important for managers of protected areas, as it allows them to better control and remove this highly invasive species, but also to prevent its further spread.

This paper presents new records and noteworthy data on the following taxa in SE Europe and adjacent regions: the diatom alga Eunotia boreoalpina; the saprotrophic fungus Clitocybe truncicola; the liverwort Haplomitrium hookeri; the moss Leptodon smithii: the monocots Epipactis purpurata, Stipa tirsa, Typha laxmannii and T. shuttleworthii; and the dicots Krascheninnikovia ceratoides, Polygonum albanicum and Sorbus latifolia.

-The aim of this paper was fi rstly to describe the ecological and geographical differentiation of the four maple species (Acer spp.) in Serbia and Kosovo based on fl oristic and phytocoenological data, and secondly, to model their distributions in order to predict which areas the species can be expected in. The intention was also to compare the resulting prediction maps with the available fi eld records and see whether there are any differences between the actual and the predicted ranges. The data set included 1979 species records and each record was accompanied by geographic coordinates. The geographical analysis was performed on the chorological data (latitude, longitude, altitude), while the ecological was based on vegetation data relating to the association, alliance, order and class as well as on 19 bioclimatic parameters. The data set was georeferenced using GIS tools. The results demonstrated that the distribution patterns of all the analyzed species are mostly affected by the limiting effects of the variables related to precipitation and temperature of the dry and also the warm period. Their synergic limiting effects are the most important force shaping distribution patterns within a territory. These fi ndings highlight the importance of defi ning bioclimatic profi les of species using different techniques of distribution modelling.