DOI: 10.2478/v10028-007-0006-8 HACQUETIA 6/2 • 2007, 131-141 THE ASSOCIATION ERYSIMO - TRIFOLIETUM MICEV. 1977 IN BULGARIA AND SOME REMARKS ON ITS MEDITERRANEAN CHARACTER Desislava SOPOTLIEVA* & Iva APOSTOLOVA* Abstract We endeavor to enlarge the knowledge about Bulgarian vegetation diversity. Data on seminatural grasslands containing 344 relevés, collected in Southeast Bulgaria were analyzed by the combine method, using TWIN-SPAN and the Cocktail method. The Erysimo diffusii-Trifolietum angustifolii association and the alliance Trifolion cherleri were established for the first time in Bulgaria. So far the presence of this association was known for Macedonia. The aims of our study are to present more data about the Erysimo-Trifolietum in Bulgaria and to make some comments about its affiliation to Helianthemetea guttati. The association is characterized ecologically and floristically. Analysis of the floristic elements shows that the most numerous are sub-Mediterranean species. Analysis of the life forms shows that these communities are hemicryptophyte-therophytic. A review of syntaxo-nomical systems and association assignment to higher syntaxa were made. According to current European vegetation surveys the association should be related to class Helianthemetea guttati. Our results reveal an intermediate character of the studied vegetation - closed dry grasslands, with distinct presence of Festuco-Brometea species with a high percent of therophytes and Mediterranean floristic elements related to Helianthemetea guttati as well. Key words: dry grasslands, syntaxonomy, Helianthemetea guttati. Izvleček Članekje prispevek k poznavanju raznovrstnosti vegetacije Bolgarije. Podatke, ki obsegajo 344 popisov, narejenih v jugovzhodni Bolgariji, smo analizirali s kombinacijo metod TWINSPAN in Cocktail. Asociacija Erysimo diffusii-Trifolietum angustifolii in zveza Trifolion cherleri sta prvič omenjeni v vegetaciji Bolgarije. Do sedaj je bila prisotnost te asociacije poznana le v Makedoniji. Namen raziskave je predstaviti dodatne podatke o asociaciji Erysimo-Trifolietum v Bolgariji in podati nekaj komentarjev o njeni uvrstitvi v razred Helianthemetea guttati. Asociacija je označena ekološko in floristično. Analiza flornih elementov je pokazala, da so submediteranske vrste najštevilnejše. Analiza življenjskih oblik pa, da je to hemikriptofitsko-terofitska združba. Opravljen je pregled sinataksonomskega sistema in uvrstitev v višje sintaksone. Po trenutnem pregledu evropske vegetacije jo uvrščamo v razred Helianthemetea guttati. Naši rezultati pa razkrivajo vmesni značaj obravnavane vegetacije - sorodnost s suhimi travniki s prisotnostjo vrst Festuco-Brometea in visokim odstotkom terofitov in z razredom Helianthemetea guttati, ki ga označujejo mediteranski elementi. Ključne besede: suhi travniki, sintaksonomija, Helianthemetea guttati. 1. INTRODUCTION The Bulgarian phytogeographic position predetermines conditions for the presence of Central European as well as Mediterranean floristic elements, i.e. respective vegetation types (cf. Bohn et al. 2003). Unlike the vegetation of most European countries, Bulgarian vegetation is still poorly studied following the floristic criteria. Up to the recent several years in the phytosociological investigations the dominance approach was applied (Apostolova & Slavova 1997). This results in questions so far unanswered, as for example "what is the diversity of alliances and associations within the class Fes-tuco-Brometea in the country", or "does Helianthemetea guttati reach the country territory"? During the Bulgarian grassland inventory (Meshinev et al. 2005) Mediterranean floristic elements in the her- * Institute of Botany, Bulgarian Academy of Sciences, Acad. Georgi Bonchev St., bl. 23, 1113 Sofia, Bulgaria 131 Hacquetia 6/2 • 2007, Knjižno poročilo/Book review, 209-217 baceous vegetation of southern Bulgarian regions, were distinguished, and the Thero-Brachypodietea class was reported for the country. The Erysimo-Trifolietum association, which is the subject of the current study, is described by Micevski (1977). This association belongs to the Trifolion cherleri Micev. 1970 alliance. It is widely distributed in the central north and northeastern parts of the Republic of Macedonia (Micevski 1977). The presence of similar communities in the territories surrounding Bulgaria poses a question about the existence of the same vegetation in the country. The aims of this study are to present more data about the Erysimo-Trifolietum association and to make some comments about its affiliation to Helianthemetea guttati. 2. MATERIAL AND METHODS The study region is situated, between 42-43° N and 26-27° E, in Southeast Bulgaria (Fig. 1). It is assigned to the Straldzha-Aitos phytogeographic region (Bondev 2002). The region is characterized by mild climate with mean annual temperatures 12.2 °C for the Aitos and Yambol, 12.4 °C for Sliven and mean annual precipitation 490.6 mm for Aitos, 567 mm for Sliven and 535.9 mm for Yambol (unpublished data provided by Bulgarian National Institute of Meteorology and Hydrology, Bulgarian Academy of Sciences). Field investigations were carried out throughout the years 2004 and 2005, according to the methods of the Braun-Blanquet School (Braun-Blanquet 1964, Westhoff & van der Maarel 1980). The data about natural and semi-natural grassland vegetation were sampled. The total number of collected relevés was 344. The standard relevé area was 16 m2 (Chytry & Otypkovâ 2003). The cover of vascular plant and bryophyte was estimated using the nine-grade Braun-Blanquet scale (Barkman et al. 1964). Altitude and coordinates were measured by GPS Garmin Etrex Summit (WGS 84 system) with altimeter calibrated by current atmospheric pressure. Slope, soil depth and soil moisture were estimated. The nomenclature of vascular plants follows Kozhuharov (1992) and the bryophyte nomenclature follows Natcheva & Ganeva (2005). The floristic elements were established according to Assyov & Petrova (2006) for the vascular plants and according to Ganeva & Düll (1999) for the bryophytes. Life forms are estimated using the data about biological types in Kozhuharov (1992). Figure 1: Points of the studied localities. / Slika 1: Lokacije proučevanih sestojev. 132 D. SopoTLiEVA, I. Apostolova: The Association Erysimo -Trifoiietum Micev. 1977 and some Remarks on its Mediterranean Character The data set was entered and stored in the TUR-BOVEG database (Hennekens & Schaminée 2001) and then exported into JUICE software (Tichy 2002). A polythetic, divisive classification that uses two-way indicator species analysis (TWINSPAN, Hill 1979) was applied. The resulting vegetation types roughly corresponded with the phytosocio-logical alliances. These vegetation types were then checked by the statistical tendency of species to have a joint occurrence in vegetation by the Cocktail method (Bruelheide 1995), using the phi-coefficient (Chytry et al. 2002). The Cocktail method and phi-coefficient were used to find the diagnostic species. Based on results of the Cocktail method, several relevés were manually moved within the groups for better representation of the diagnostic species groups. All undetermined groups were removed from the subsequent analysis. As a result the amount of 175 phytosociological relevés was classified into six alliances, and in the synoptic tables species were ranked according to their fidelity value for individual clusters (Sopotlieva in press). Fidelity was calculated by the phi-coefficient of association, applied to the classified data set with equalised sizes of clusters according to Tichy & Chytry (2006). Within the alliances, the associations were recognized after referring to the appropriate literature. Soil samples were collected in the studied area at 5-10 cm depth and basic soil properties (pH, electrical conductivity, humus content, concentration of CaCO3) were analysed. The samples were air-dried. The pre-treatment of samples for chemical analyses follows ISO 11464:1994 (E). Electrical conductivity (EC) and pH were measured in water solution using a 1:5 soil:water ratio and using pH-meter Jenway3310 (ISO 10390:1994 (E)). CaCO3 concentration was measured in 1:10 water solution using Photometer PC 22, the results are presented as mg/l. Humus was determined according to the modified Turin method (Kononova 1966). All the analyses were performed in the Analytical Laboratory, Department of Phytocoenology and Ecology in the Institute of Botany, Bulgarian Academy of Sciences. 3. RESULTS AND DISCUSSION Detailed sampling of grassland diversity in the Straldzha - Aitos phytogeographic region revealed the presence of Trifolien cherleri alliance. All relevés confined to this cluster were homogenous and obviously belong to one association. So far several different associations are described within this alliance (Micevski 1972, 1973, 1977, Micevski & Mat-evski 1984, Matevski & Kostadinovski 1998). Based on the diagnostic species group, in the studied region appears the association Erysimo-Trifolietum Micev. 1977. It is documented by 18 phytosocio-logical relevés and is reported for the first time for Bulgaria. Characteristics of the association in Bulgaria Our investigation shows that its communities predominantly cover terrains with sunny expositions and slopes up to 15°. Soils are shallow or with medium depth and dry. So, the terrains are similar to those in Macedonia, as compared with the data published by Micevski (1977). The altitude ranges between 200 and 350 m, while in Macedonia it reaches up to 900 m above sea level. From the mean values of the examined soil parameters it appears that in Bulgaria the association Erysimo-Tri-folietum grows on slightly acidic to neutral soils (average pH 6.22) with average electrical conductivity 37.3 pS.cm-1. The organic matter varies, but most often it is between 2-3 %, which corresponds with the considerably low nutritient availability. CaCO3 has an average content of 51.3 mg.l-1 (Table 2). The floristic composition of the association is shown in Table 1. The plants diversity includes 161 taxa. The average number of species per relevé is 31.4. As compared with the relevés published by Micevski (1977) species diversity in Macedonia is higher. The association character species, in our data (Trifolium angustifolium, Vulpia myurus, Erysimum diffusum, Trifolium striatum ) (Table1) includes species with highest constancy among the character species for the association, as described by Micevski (1977). In Bulgaria these species grow in dry grasslands communities in lowlands and hilly regions (Kozhuharov 1992), and thus they correspond well to the ecological conditions, occupied by the communities of the association. The Trifolion cherleri alliance is represented by 11 species (Table 1). The relatively low constancy (II) of most of the species, which belong to alliance Trifolion cherleri, including the clover Trifolium cher-leri, could be explained by the fact that our data were sampled from the region situated further north than the still known areal of the association. Micevski (1977) mentions that northward the com- 133 Hacquetia 6/2 • 2007, Knjižno poročilo/Book review, 209-217 munities start to lose some diagnostic species. According to him, among the other Trifolion cherleri associations (Tunico-Trisetum myrianthiMicev. 1972, Helianthemo-Euphorbietum thessalae Micev. 1973, Di-antho-Cistetum incani Micevski & Matevski 1984, Biserrulo-Scleranthetum dichotomae Matevski & Kos-tadinovski 1998), Erysimo-Trifolietum association has the most continental character. The author states also that this is obvious by the decreasing number, abundance and constancy of the Mediterranean species. The clover Trifolium cherleri, the most character species to the alliance, has a V degree of constancy in the associations Tunico-Trisetum myrianthi and Helianthemo-Euphorbietum thessalae, but in the Erysimo-Trifolietum it has different constancy in the different areas or does not occur in all the localities of association in Macedonia. The analysis of the floristic elements shows that the most numerous are sub-Mediterranean species (28), followed by Euro-Asiatic (25); Euro-Mediterranean and Euro-sub-Mediterranean (24); Mediterranean (16); boreal and sub-boreal (10); Pon-tic-Mediterranean (9); Pontic and Pontic-Siberian (9); Balkan, Balkan-Dacian, Pannonian-Balkan and Apenninian-Balkan (9). The other types contain 7 or less than 7 species (Table 1). Thus the Mediterranean floristic element (including Mediterranean, sub-Mediterranean, Euro-Mediterranean and Euro-sub-Mediterranean) has a convincing presence in the studied vegetation (42 %). Analysis of the types of life forms shows that these communities are hemicryptophyte-thero-phytic, which also emphasizes their southern affiliation (Table 1). The therophytes are 68 species (42 %). The other approximately one half of the species are hemicriptophytes. Association assignment to the higher syntaxonomical level As proposed by the Braun-Blanquet School, assignment of an association to an alliance (and other higher units) is primarily based on comparison of floristic relationships (westhoff & van der Maarel 1980). In this respect, in the original data (Micevski 1977), as well as in our data, the Erysimo-Trifolietum association contains a well-defined group of diagnostic species of alliance Trifolion cherleri and undoubtedly belongs to this alliance. The Trifolion cherleri alliance is described as "sil-icicolous therophyte swards of submediterranean character in Macedonia and northern Greece" (Rodwell et al. 2002). This alliance has not been established in Bulgaria so far. Thus our results prove its enlargement to the North-East. The position of the alliance Trifolion cherleri in the syntaxonomical system and its relation to higher syntaxa is problematic. when it was described, it was assigned to the order Astragalo-Potentilletalia Micev. 1970 without any decision about the affiliation to a class (Micevski 1970). In the later publications (Micevski 1978; Micevski & Matevski 1984) the alliance as well as the order was assigned to the class Festuco-Brometea. This class includes grasslands of the temperate and sub-boreal regions (Mucina 1997). Such position presumes a more continental character of the communities of the alliance. According to the current syntaxonomical vision about European vegetation (Rodwell et al. 2002), Trifolion cherleri belongs to Helianthemetalia guttati Br.-Bl. in Br.-Bl., Molinier & Wagner 1940 and Heli-anthemetea guttati (Br.-Bl. in Br.-Bl., Roussine & Nègre 1952) Rivas Goday & Rivas-Martmez 1963 em. Rivas-Martmez 1978, which perceives its Mediterranean character. Analysis of the floristic composition of the Ery-simo-Trifolietum association in Straldzha-Aitos phy-togeographic region shows that order Astragalo-Po-tentilletalia is represented by 15 diagnostic species and class Festuco-Brometea is represented by 30 diagnostic species (Table 1), while to the Helianthemeta-lia guttati belong 7 such species. Class Helianthem-etea guttati is represented by 7 species, but four of them occur only in one relevé. These results reveal an intermediate character of studied vegetation -closed dry grasslands, with distinct presence of Fes-tuco-Brometea species as well with a high percent of therophytes and Mediterranean floristic elements. In the monograph about the class Festuco-Brometea Royer (1991) comments on the existence of het-erogenic groups in Bulgaria, Macedonia, Serbia and probably in Greece, which belong to the class Thero-Brachypodietea with penetrating Festuco-Brom-etea species. Royer (1991) states that the border between these two classes probably lies in Southern Bulgaria. The studied vegetation type the author assigns to Astragalo-Potentilletalia and Thero-Brachy-podietea, i.e. to the vegetation with Mediterranean character. In some overviews of the Balkan Peninsula vegetation (Horvat et al. 1974; Wendelberger 1965) Trifolion cherleri is not mentioned. Recently, critical revision of Helianthemetalia guttati (Pérez Prieto & Font 2005) considers only West Mediterranean and does not include this Balkan alliance. 134 D. SopoTLiEVA, I. Apostolova: The Association Erysimo -Trifoiietum Micev. 1977 and some Remarks on its Mediterranean Character Even at the broad level of classes, different syntax-onomical schemes were proposed without universal acceptance. During the development of syntaxono-my, within the sandy dry grasslands and related vegetation types of Europe, different vegetation classes were described (Dierschke 1986). Among them, according to Mucina (1997), classes Helianthemetea gut-tati and Poetea bulbosae are syntaxonomical synonyms of class thero-Brachypodietea. Rodwell et al. (2002) published the more finely divided scheme and accepted Helianthemetea guttati and thero-Brachypodietea ramosi as distinct classes within Mediterranean vegetation. This reveals the need of critical revision for dry grassland vegetation in South-East Europe. 4. CONCLUSIONS The erysimo-trifolietum association as well as the trifolion cherleri alliance is distributed in Bulgaria. Despite the fact that these syntaxa are documented only by 18 relevés, the intermediate character of the studied vegetation between the continental and Mediterranean dry grasslands is obvious. This is witnessed by the statements (Royer 1991) that the border between Festuco-Brometea and Helianthemetea guttati lies in Southern Bulgaria. 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Apostolova: The Association Erysimo -Trifoiietum Micev. 1977 and some Remarks on its Mediterranean Character Table 1: Erysimo-Trifolietum association. Tabela 1: Asociacija Erysimo-Trifolietum. Number of relevé 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Altitude [m] Exposition Cover [%] Number of species "C B « S O I oo ^o ^o oo -H -H ^ ^O OO OO CN CN S W s WEWSSWNSNW WNSWS 80 95 90 70 90 95 85 90 100 85 85 75 95 90 85 85 85 85 26 34 28 30 31 32 27 46 38 19 30 30 28 33 37 34 32 31 U Char. for Association Trifolium angustifolium Th med + + + + + 1 + + + + + IV Vulpia myurus Th subboreal 2m 2b 2a + + 2b + II Erysimum diffusum H eur + + 1 + + II Trifolium striatum Th eur-med 1 + + + + II Trifolion cherleri Trifolium arvense Th eur-sib 1 + + 1 + + 1 + + + + + + + IV Rumex acetosella H eur-submed 1 1 + 1 + + + 1 1 1 + IV Logfia minima Th eur-sib + + + + + + II Petrorhagia prolifera Th pont-med + 1 + + + + r II Trifolium cherleri H med 1 2m + + + II Vulpia ciliata Th med-as + 2b 1 2b 2a II Taeniatherum caput-medusae Th eur-as + + + + + II Aira elegantissima Th med 2m 2a + + + II Linaria pelisseriana Th med + + + + II Silene subconica Th submed 1 I Sedum caespitosum H med + I Helianthemetalia guttati Psilurus incurvus Th submed + + + + 1 1 + + + 1 1 IV Trifolium strictum Th eur-sib + + + + II Filago lutescens Th boreal + I Helianthemetea guttati Trifolium campestre Th eur-med 1 + + + + + 1 + + + + + + + 2a + V Arenaria leptoclados Th eur-as + + + + + + II Medicago minima Th eur-as 1 + 2b 2b II Cerastium pumilum Th eur-med + + + I Scleranthus polycarpos Th submed 1 I Arenaria serpyllifolia Th eur-as + I Acinos arvensis Th eur-med + I Festuco-Brometea Eryngium campestre H pont-med + + + 1 + 1 + + + 1 + + + + 1 + V Poa bulbosa H eur-as 2m 1 3 + + + + 3 + + 2a 1 1 1 IV Sanguisorba minor H subboreal + 1 + 1 + + + 1 + + + + 1 1 IV Thymus striatus H submed + 2a 1 1 2b + + + + 1 + + IV Festuca valesiaca H pont 2b 2b 2a 4 2b 2a + 1 2a III Chondrilla juncea H eur-sib + + + + + + r + + III Euphorbia cyparissias H eur + r 1 + + r 1 + III Koeleria nitidula H pont + + + + r 4 2a + + III Chrysopogon gryllus H pont-med 2b r 4 r 2a 3 II Galium verum H eur-as 2a + + + + + II 137 Hacquetia 6/2 • 2007, Knjižno poročilo/Book review, 209-217 Number of relevé 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Dichantium ishaemum H med-as + 1 + 3 + 2a + Teucrium polium H pont-med + + + + + + Achillea crithmifolia H pann-bal + + + + 1 1 Hieracium praealtum H + + + + + Trifolium scabrum Th med-as + + + + Convolvulus cantabrica H pont + + + 1 Centaurea rhenana H submed + + + + Asperula cynanchica H eur-med + + r + Hypericum perforatum H cosm + + r Euphrasia stricta Th eur-med + + Linaria genistifolia H pont-sib r + Hieracium hoppeanum H eur-med r + Dasypyrum villosum H submed + + Helianthemum nummularium Ch alp-med 1 + Carthamus lanatus Th submed 1 Stipa capillata H pont-med r Achillea nobilis H eur-as 1 Alliumflavum K med + Teucrium chamaedrys H submed + Astragalus onobrychis H eur-as + + Other species Anthemis ruthenica Th submed + + + r 3 + + 1 r + + Plantago lanceolata H cosm + + 1 1 + 1 + 2a 2a + + Crepis setosa Th eur-med + + + 1 + + 1 + r Scleranthus perennis H eur-med 3 + 1 + + + + + Bromus squarrosus Th submed + 1 + + 2m r + Lotus angustissimus Th med + + + + + + r Galium tenuissimum Th pont-as + + 1 + + Stachys angustifolia H pont-med + r + + + Potentilla inclinata H eur-as + + + r + Ceratodon purpureus H cosm;temp + 1 + + + 1 1 Ornithogalum umbellatum K pont-submed + + + + + + Potentilla argentea H pont + + + + + + Cichorium intybus H eur-sib + + + r + + Syntrichia ruralis H cosm;temp 1 1 + + 1 Brachythecium albicans H subboreal 2a 1 2a 2a 2a Bombycilaena erecta Th eur-med + + + r + Hypochaeris radicata H eur-med + + r r r Erodium cicutarium Th subboreal + 1 1 + Echium vulgare H eur-as + r r + + Herniaria hirsuta Th eur-as + + + + + Jasione heldreichii H eur-med r r + + Vicia grandiflora H submed + + r + Cynodon dactylon H cosm + + 1 + + Filago vulgaris Th eur-as + + + + Hypericum rumeliacum H bal + + + Euphorbia myrsinites H submed r + Xeranthemum annuum Th submed + + Aegilops triuncialis Th eur-as + 138 D. SopoTLiEVA, I. Apostolova: The Association Erysimo -Trifoiietum Micev. 1977 and some Remarks on its Mediterranean Character Number of relevé Ziziphora capitata Th med Velezia rigida Th submed Plantago subulata H med Veronica arvensis Th eur-sib Trifolium retusum Th med Leontodon crispus H pont-med Centaurium erythraea H submed Verbascum adrianopolitanum H bal Dianthus pinifolius H bal-dac Sedum acre H eur-med Achillea coarctata H pont-med Dactylis glomerata H eur-as Agrostis canina H eur-sib Cynosurus echinatus H submed Viola arvensis Th eur Bromus tectorum Th boreal Hypericum thasium H bal Dianthus armeria Th eur Alyssum desertorum Th eur-med Rorippa thracica H submed Sideritis montana Th submed Potentilla neglecta H subboreal Echinops ritro H eur-sib Centaurea diffusa H pont-med Anthoxanthum odoratum H eur-as Gypsophila muralis H eur-as Trifolium diffusum Th submed Orlaya kochii Th eur-as Geranium rotundifolium Th eur-as Verbascum thapsiforme H submed Koeleria macrantha H eur Orlaya grandiflora Th ap-bal Filipendula vulgaris H eur-med Chamomilla recutita Th eur-as Dorycnium herbaceum H eur-med Reseda lutea H subboreal Dianthus moesiacus H bal Trifolium setiferum Th med Phleum phleoides H eur-as Erysimum repandum Th eur-as Sherardia arvensis Th med Astragalus hamosus H eur-as Trifolium incarnatum Th submed Carduus nutans H eur-med Medicago lupulina Th eur-as Allium vineale K eur-NAm Convolvulus arvensis H cosm Trifolium repens H eur-sib Tragopogon dubius H eur-med 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 2a + + . r r . .r .+ 2m .+ r. 2b + 2a 1 + + + + 1 + + r + + + + 4 r 1 + + + + + + r ++ + + + 3 + r r r + + + r + + + + + + + + + + 139 Hacquetia 6/2 • 2007, Knjižno poročilo/Book review, 209-217 Number of relevé 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Marrubium peregrinum H submed . . r Muscari sp. K . . + Lotus corniculatus H eur-med . . . . . + . . Dianthus pallens H bal-dac . . +. Bromus arvensis Th eur-as . . .....+ Chenopodium botrys Th boreal . . . 2a Ferulago sylvatica H submed . . .. 1 Racomitrium canescens H boreal . . . . . + Verbascumfloccosum H submed . . .....+ Trifolium purpureum Th med . . r . . . . . Centaurea cyanus Th eur-med . . r . . Lathyrus nissolia Th eur-med . . .....+ Scabiosa triniifolia Th bal . . .. 1 Valerianella coronata Th eur-med . . r . . Ornithopus compressus Th submed . . . . + . Trifolium echinatum Th med . . .....+ Pterygoneurum ovatum H temp . . .....+ Euphorbia chamaesyce Th eur-as . . . 2a Salvia argentea H med . . r Bryum caespiticium H temp . . .. 1 Barbula unguiculata H .....+ Xeranthemum cylindraceum Th submed . . .....+ Poa angustifolia H cosm . . . r . . Coronilla scorpioides Th submed . . .....+ Anthemis tinctoria H eur-sib + . Alyssum hirsutum Th submed . . .....+ Crucianella angustifolia Th med . . .....1 Melica ciliata H eur-submed . . . . + Viscaria vulgaris ssp. atropurpurea H eur-sib . . . . . + Localities: 1.-E of the Tvarditzha town, 42.67839° N, 25.95018° E, 10.06.2005; 2.-North slopes of Sredna Gora mountains, S of the Tvarditzha town, 42.64797° N, 25.92345° E, 14.06.2005; 3.-Svetiilijski vazvishenia hill, N of Sokol village, 42.41123° N, 26.10004° E, 11.06.2005; 4.-E of Zlatari village, 42.3847° N, 26.2315° E, 29.06.2004; 5.-W of Nautchen village, 42.56536° N, 26.08056° E, 20.07.2004; 6.-the Golina hill near Tvarditzha town, 42.68123° N, 25.92186° E, 09.06.2005; 7.- North slopes of Sredna Gora mountains, S of Tvarditzha town, 42.65615° N, 25.92084° E, 14.06.2005; 8.-NW of Peshtersko village, 42.75153° N, 27.33362° E, 22.07.2005; 9.-E of Zlatari village, 42.38478° N, 26.23153° E, 29.06.2004; 10.-E of the Sliven town, 42.6686° N, 26.4010° E, 25.07.2004; 11.-S of Kozharevo village, 42.68975° N, 25.87724° E, 06.06.2005; 12.-W of Nautchen village, 42.5653° N, 26.0805° E, 20.07.2004; 13.-North slopes of Sredna Gora mountains, S of the Tvarditzha town, 42.64839° N, 25.92273° E, 14.06.2005; 14.-Sredna Gora mountains, near the Zhrebtchevo dam, 42.60160° N, 25.91573° E, 14.06.2005; 15.-E of Banja village, 42.61227° N, 26.00080° E, 10.06.2005; 16.-S of Kozharevo village, 42.68935° N, 25.87649° E, 06.06.2005; 17.-near the Zhrebtchevo dam, 42.63688° N, 25.89264° E, 14.06.2005; 18.-the Marashka Mogila hill, N of mezhda village, 42.36735° N, 26.25332° E, 29.06.2004. 140 D. SopoTLiEVA, I. Apostolova: The Association Erysimo -Trifoiietum Micev. 1977 and some Remarks on its Mediterranean Character Table 2: Ecological characteristics of the sampled relevés. Tabela 2: Ekološke značilnosti vzorčenih popisov. relevé slope soil depth soil moisture pH EC humus CaCO3 [°] foS. cm1] [%] [mg. l-1] 1 0 medium dry 6,12 24 7.98 78 2 5-10 medium dry 6,2 30 3,7 35 3 1-5 medium dry 5,95 29 2,13 36 4 10-15 medium dry - - - - 5 5-10 shallow dry - - - - 6 10-15 medium dry 6,45 63 13,88 96 7 1-5 shallow dry - - - - 8 10-15 shallow dry - - - - 9 1-5 medium dry 7,06 79 1,79 96 10 0 shallow dry - - - - 11 0 shallow dry - - - - 12 1-5 shallow dry - - - - 13 5-10 medium moderatly moist 6,41 23 3,10 33 14 10-15 shallow dry 6,03 22 2,33 32 15 10-15 shallow dry 6,41 40 3,46 43 16 0 shallow dry - - - - 17 1-5 medium dry 6,11 20 3,4 28 18 10-15 shallow dry 5,44 43 1,04 36 141