CONTRIBUTION TO KNOWLEDGE OF THE VASCULAR FLORA OF THE RESAVA GORGE, EASTERN SERBIA

The Resava Gorge is situated in Eastern Serbia in the region of the Gornja Resava River, extending westward from Mt. Globski Krš to the town of Lisine. In floral research conducted during 1997 and 1998, 297 taxa of vascular flora belonging to 68 families were discovered. The families Poaceae (28), Asteraceae (21), Fabaceae (20) and Lamiaceae (19) were best represented. The presence of 49 floral elements was also noted. The greatest number of plants are sub-Central European (18,86 %), Eurasian (14,14 %), sub-Mediterranean (8,75 %), Central European (6,40 %) and subEurasian (6,40 %). As for life forms, hemi-cryptophytes (49,50 %), phanerophytes (19,53 %) and geophytes (11,11 %) were noted as dominant.

Arch.Biol. Sci.,Belgrade,59 (1), 75-80, 200775-80, . DOI:10.2298The flora of the Resava Gorge was first mentioned in "Flora Kneževine Srbije" (Flora of the Principality of Serbia) by P a n č i ć (1874).Investigations were also conducted by J o v a n o v i ć (1970), D i k l i ć (1970), T u c o v i ć (1970), G a j i ć (1970)(1971)(1972), N i k o l i ć (1972), S t a j i ć (1972), V u k i ć e v i ć (1992), and others.Relict vegetation in this region was researched and described in studies of M i š i ć (1971,1981,1982), with special emphasis on forest communities.

MATERIALS AND METHODS
Seasonal research on flora in the Resava Gorge was conducted in 1997 and 1998 from Lisine to Globski Krš, in the canyon of the Suvaja, and on the slopes of Mt.Beljanica (Golovršac locality).
The collected plants were herbarized according to the method of J a n k o v i ć (1971) and deposited in the Institute of Botany and Jevremovac Botanical Garden.
The files opened for every plant species contain information about the area, locality, altitude, exposure and slope, geological base, and soil type in the place where the species was found.Identification of plant taxa was carried out according to "Flora SR Srbije"  and "Iconographia Florae Partis Austro-orientalis Europae Centralis" (1975).
The life forms defined by R a u n k i e r (1934) are supplemented and developed according to Stevanović (1992) and Jovanović (1994).
Further analysis demonstrates the presence of 187 genera.Of these, Trifolium (eight), Campanula (eight), Galium (seven), and Acer (six) have the greatest number of species.
There are 49 floristic elements in the vascular flora of the Resava Gorge, belonging to nine range types.The greatest number of species (27,95 %) belong to the Eurasian range type.In the Moesian province, the Eurasian floristic element is represented with just 14,13 % (Gajić, 1984).That points to great diversity of habitats and ecological factors in the region of the Resava Gorge, as well as to its refugial character.Fifteen of the total number of Eurasian species [Cornus mas L.(Pontic-sub-Mediterranean), Cotinus coggygria Scop.(Pontic-Central Asian-sub-Mediterranean), Allium flavum L. (Pontic-Central Asian-sub-Mediterranean) etc.] represent a connection between xerothermal Mediterranean -sub-Mediterranean habitats and steppes and forest-steppes of Europe and Asia, their presence occuring due to specific climatic conditions in the gorge created by collision of different climatic influences from the mentioned regions.As for the Eurasian range type, the greatest number of plants ( 19) belong to the floristic element of the same name: Juniperus sabina L., Calamagrostis varia (Schrad.)Host., Epipogium aphyllum S. W. etc.
In second place is the Central European range type, with 88 taxa.The greatest number of species belong to the category of sub-Central European floristic elements (18,86%).
According to G a j i ć (1984), species of this range type found optimal conditions for their survival in oakhornbeam forests, in which they participate with 20,76%.In these communities, Central European floristic elements are represented with 14 species (4,26%), indicating that the flora of the Resava Gorge is connected to the Central European floristic region through transitional floristic elements (G a j i ć, 1984).
The significant number of microhabitats with specific ecological conditions resulted in the occurence of a great number of herbaceous species especially hemicryptophytes, which are represented with 147 species (49,50 %) in the flora of the Resava Gorge -a percentage higher than in the flora of the Republic of Serbia (46,8 %).
With respect to the spectrum of life forms, geophytes (11,11%) were in third place in the flora of the investigated area.Oxalis acetosella L., Pteridium aquilinum (L.) Kuhn., Equisetum telmateia Ehrh., and others were found in humid habitats with low radiant energy.

Table 1 .
Vascular flora of the Resava Gorge.