Contribution to the Orophilous Cushion-Like Vegetation of Central-Southern and Insular Greece

The results of a phytosociological investigation regarding the orophilous cushion-like vegetation occurring in the top of the high mountains of central-southern Greece and in some Ionian (Lefkas, Cephalonia) and Aegean Islands (Euboea, Samos, Lesvos, Chios and Thassos) are provided. Based on 680 phytosociological relevès (460 unpublished and 220 from literature), a new syntaxonomical arrangement is proposed with the description of a new class, including two new orders, eight new alliances, and several associations (many of them new). Compared to the previous hierarchical framework usually followed in the literature, this study provides a more realistic and clear phytosociological characterization of this peculiar and archaic vegetation type, which is exclusive to the high mountains of the north-eastern Mediterranean. The new arrangement is mainly based on the phytogeographical role of the orophytes featuring this very specialized vegetation, which is essentially represented by endemics or rare species belonging to the ancient Mediterranean Tertiary flora. In addition, taxonomic research on the orophilous flora occurring in these plant communities allowed to identify six species new to science (i.e., Astragalus corinthiacus, Allium cremnophilum, A. cylleneum, A. orosamium, A. karvounis, and A. lefkadensis) and a new subspecies (i.e., Allium hirtovaginatum subsp. samium), and two new combinations (i.e., Astragalus rumelicus subsp. euboicus and subsp. taygeticus) are proposed.


Introduction
The orophilous cushion-like vegetation colonizing the cacuminal stands of the highest mountains of the Mediterranean territories has always aroused a lot of interest from botanists, mainly for the occurrence of a peculiar and specialized flora. It is represented usually by relict taxa (species and subspecies), mainly endemic adapted to hard environmental conditions, which are aggregated in physiognomically well differentiated plant communities [1,2].
Many plants that characterize these phytocoenoses (usually localized at high altitude) belong to the ancient Tertiary Mediterranean flora. They are represented mostly by dwarf nanophanerophytes and chamaephytes mixed with caespitose hemicryptophytes which form plant communities often covering large surfaces. This ecologically specialized vegetation is associated and adapted to long wintry periods of lasting snow cover (sometimes till late spring), as well as to prolonged summer droughts with intense winds. It occurs mostly on rocky places with undeveloped and immature soils due to the prevailing harsh climatic conditions and wide diurnal and annual variations. Such factors seem to converge to climatic conditions of the temperate cold climate inserted in the Mediterranean context [3].  The substrates are essentially constituted by carbonate rocks, consisting mostly of Mesozoic dolomites and limestones. The landscape is mainly rocky with walls and dolines. The bioclimate between 1000 and 1500 m falls within meso-Mediterranean sub-humid, while up to 2000 m is of supra-temperate sub-Mediterranean type; over 2000 m it is replaced by oro-temperate sub-Mediterranean one. The average annual temperatures range between 11 • C and 5 • C, related to the altitude, while the annual rainfall average ranges from 800 to 1000 mm. Up to about 1700 m scattered forests dominated by Abies cephalonica occur, which are usually mixed to dwarf shrubs conipher communities and cushion-like orophilous vegetation: the latter, becomes dominant above 1700 m of altitude. Previously, these shrub communities were investigated by Quézel [35]. •

Mt. Giona
It is a large mountain massif with rather blunt peaks spread over a large area. The highest peak is Piramídha (2507 m), followed at lower altitudes by Traghonoros (2456 m The substrates are mostly constituted by Mesozoic dolomites with numerous plateaux and valleys and scattered dolines. In this area the bioclimate has the same characteristics as that shown for the Mount Parnassus: in particular, the annual average temperatures range between 10 • C and 5 • C, while the mean annual rainfall is between 800 and 1000 mm. According to Quézel [35], the timberline of Abies cephalonica forests is around 1700 m, while above this altitude, the landscape is dominated by cushion-like shrubs, often mixed to grasslands.
Panachaiko is the mountain range with the northernmost position than any other mountain in the Peloponnese. It is located south of Patras, peaking almost 2000 m of elevation. Its summit reaches, in fact, 1924 m and is characterized by ridges with rocky walls overhanging extended screes. The substrates consisting of dolomites and limestones dating back to the Mesozoic, usually with very sloped and rocky surfaces. From a bioclimatic point of view, this mountain area falls mainly within the meso-Mediterranean belt, and only in the highest part, above 1600-1700 m, it tends toward the supra-temperate sub-Mediterranean one. The ombrotypes range from the sub-humid to humid, with average annual rainfall reaching 1000 mm. The annual average temperatures range between 8 • C and 10 • C. Due to the remakable acclivity of the surfaces, the orophilous cushion-like communities are quite widespread and well represented from the 1500-1600 m of altitude. Currently, there are no phytosociological data about this type of vegetation on this mountain. At altitudes below 1600 m, the surfaces are affected by a meso-Mediterranean termotype. As regards the ombrotype, it ranges from the lower to the upper humid, with average annual rainfall of 1000-1400 mm. The annual averages temperatures are around 8-5 • C, with significantly lower values on the eastern side which is characterized by a higher continentality. The tree vegetation is represented by woodlands of Abies cephalonica, that are widespread up to 1600-1700 m, while at higher altitudes, not exceeding 1800-1900 m, there are examples of open and spaced dwarf woods of Juniperus foetidissima, usually mixed with cushion-like communities, that in the higher peaks become dominant. Previously, a study of this hemicrypto-chamaephytic orophylous vegetation, was carried out by Maroulis and Georgiadis [44]. •

Mt. Klokos
This mountain is located at south-east of M. Panachaiko, characterized by carbonatic substrates consisting mainly of dolomites. The summit reaches 1778 m in altitude and coincides with the uppermost part of a large rocky face. The landscape is very rough due to the presence of ridges, very steep slopes, and screes. This mountainous area is characterized by a bioclimate falling mostly in sub-humid meso-Mediterranean belt which, at the summit, tends toward the supra-temperate sub-Mediterranean one. Average annual temperatures range between 8 • C and 9 • C, while the average annual rainfall reaches 900-1000 mm. The highest part of the mount is essentially characterized by thorny pulvinate communities, covering the most part of the surfaces. So far, there are no studies on the vegetation of this mountain. The substrates consist mainly of Mesozoic limestones and dolomites, sometimes with outcrops of marls and clays. The landscape is very harsh and rugged with numerous ridges, very steep slopes, screes and valleys. At elevations higher than 1500-1600 m, the bioclimate falls into supra-temperate sub-Mediterranean belt, while above 1800-1900 m of altitude it is of oro-temperate sub-Mediterranean type, with average annual temperatures between 9 • C and 5 • C. The ombrotype is comprised between the upper sub-humid and the lower humid, with annual average rainfall reaching 900-1200 mm. In the mountain belt, at an altitude lower than 1500 m, the bioclimate is attributable to meso-Mediterranean sub-humid. The forest vegetation is represented by Abies cephalonica woodlands or, limitedly to marly substrata, by pine wood of Pinus pallasiana. In the higher stands, coinciding with the peaks and the steep rocky slopes, the surfaces are covered by orophilous pulvinate communities. Investigations on this vegetation, were previously carried out by Quézel and Katrabassa [40].

•
Mt. Killini Mt. Killini, also known as "Ziria", is a mountain range with several peaks topping 2000 m in altitude, including Megali Ziria or Simio (2374 m), Profitis Ilias (2259 m), Kokinovrakos (2168 m), Michri Ziria or Kioni (2082 m), Paraga (2032 m), and Tsouma (2021 m). It is located in the north-eastern sector of the Peloponnese, at south-east of Mt. Chelmos. The substrates are mostly of carbonatic origin and are represented by dolomites and various types of limestones (bioclastic blackish, in plaques or compact). The landscape is quite soft with smoothed summits, interspersed with dolines and plateaux, while poorly developed are the rock walls and screes. Below 1800 m, the bioclimate falls into supra-temperate sub-Mediterranean belt, while above 1800-1900 m falls into oro-temperate sub-Mediterranean one, with ombrotype upper sub-humid. Average annual temperatures in relation to the altitude, range from 10 to 6 • C, with average annual rainfall comprised between 900 and 1000 mm. The mountain forests between 1400 and 1800 m are represented by open woodlands with Juniperus foetidissima or sometimes Acer monspessulanum, usually mixed with orophilous pulvinate communities that above 1800 m become dominant. Previously, phytosociological investigations were carried out by Quézel [35] and Georgiadis and Dimopoulos [42]. •

Mt. Menalon
It is a small mountain range, located at north of Tripoli, in the north-central part of the Peloponnese. The highest peaks are Ostrakina (1980 m), Tzeláti (1875 m) and Kendhrovouni (1730 m), showing not much sloping and bland surfaces. The substrates are prevalentely represented by limestones in plaques and dolomites. The bioclimate above 1500-1600 m of altitude, falls into supra-temperate sub-Mediterranean belt, with annual average temperatures of 9-8 • C, and annual average rainfall of 900-1000 mm. In the highest part, the vegetation is mainly represented by orophilous pulvinate communities, while at elevations lower than 1500 m occur Abies cephalonica woodlands. So far, this mountainous area had not yet been investigated from the phytosociological point of view. The massif has a north-south direction with peaks rather mild interrupted by wide valleys that give a marked discontinuity. The bioclimate falls within Mediterranean Oceanic Pluviseasonal with thermotypes between meso-Mediterranean, at altitudes lower than 1500 m and supra-Mediterranean at higher altitudes. The ombrotype is attributable to sub-humid, with annual average rainfall of 900-1000 mm. The annual average temperatures are around 10-9 • C or even lower (7)(8) • C) at the highest peaks. Currently, the woodlands appear very degraded with patches occurring up to an altitude of 1600-1700 m, and are characterized by the dominance of Abies cephalonica. Instead, the pulvinate thorny communities are widespread and well represented in the summit stands. Currently, no vegetation data are available on this mountain range. Geologically it is mainly constituted by compact limestones, with schist outcrops especially at lower altitudes. The landscape is very rough due to the presence of numerous ridges and peaks with slopes quite steep and rocky. Screes and cliffs are common, as well as plateaux with scattered dolines. The bioclimate is Mediterranean with oceanic pluviseasonal thermotypes ranging from the supra-and oro-Mediterranean in relation to altitude, while the ombrotype is in the top sub-humid. Annual average temperatures above 1500 m vary between 9 • C and 7 • C, while the annual average rainfall of between 900 and 1000 mm. On this mountain the forests occurring at high altitudes are represented by Abies cephalonica woodlands, which are frequent up to 1800 m. They usually are linked to carbonatic substrata, while on scists they are replaced by Pinus pallasiana woods. Some example of orophilous pulvinate vegetation can be observed from 1200 m of altitude limitedly to the areas with rocky outcrops, penetrating inside of the forest belt. These communities become dominant above 1800 m up to the highest peaks. This kind of vegetation was previously investigated by Quézel [35].

Island Mountains
•

Lefkas Island
It is about 100 m from the mainland, with which it is connected by a floating bridge. The highest mountain of the island is Mt. Elati (1158 m), also known as Mt. Stavrota, charaterized by some peaks, as Agios Elias, Pirgos, and Mega Oros. This mountain is covered with phrygana communities, which is replaced by orophilous pulvinate communities in the summit, while the forests are currently absent. The substrata are mainly represented by Mesozoic limestones and the bioclimate falls within the meso-Mediterranean with sub-humid ombrotype. peak in Mt. Megas Soros with an elevation of 1628 m, while the second peak towards north-west is Mt. Roudhi, which rises to 1125 m. The bioclimate in the higher stands is typically oro-Mediterranean with sub-humid ombrotype. The slopes between 700 and 1200 m are covered by pine forests and above this altitude there are forests dominated by Abies cephalonica. The very windy ridges and the rocky plateaux, located at an altitude not lower than 800 m, are charaterized by a pulvinate dwarf shrub vegetation very rich of endemic orophytes. Observations of this type of vegetation are reported by Knapp [59]. •

Euboea Island
The mountains in the Euboea Island, or Evvia, that for dimensions is the second largest island in Greece after Crete, are numerous and well represented. The main peaks are Mt. Dirfis (1743 m), Mt. Ochi (1394 m), and Mt. Pyxaria (1341 m), constituted by metamorphic substrata (scists) mixed to triassic marbles. The highest summits are usually affected in by a oro-Mediterranean bioclimate, tending to meso-temperate sub-Mediterranean one, with sub-humid ombrotype. The orophilous dwarf shrub vegetation is well represented in the mountain summit of this island and in particular on Mt. Dirfis. No data on these orophilous communities are reported in literature.

Samos Island
On the Island of Samos (East Aegean), the peaks with altitudes above 1000 m are Mt. Kerkis (1433 m) and Mt. Ambelos (1153 m). Geologically, Mt. Kerkis consists of Mesozoic limestones, while Mt. Ambelos (or Karvounis) is mainly represented by schists and marbles. The bioclimate affecting these mountains falls within the meso-Mediterranean belt, with sub-humid ombrotype. In the summits of these mountains, above 1000 m of altitude, are located orophilous pulvinate communities, often dominated by echinophytic shrubs. Previously, some observations of this vegetation in Samos were reported by Christodoulakis and Georgiadis [41].

Lesvos Island
Lesvos (or Lesbos), near to the Turkish coast, is mainly mountainous with an important large peak, represented by Mt. Olympus (967 m), located in the southern part of the island. The top of this mount is constituted by an outcrop of Mesozoic crystalline limestones, with very steep and eroded slopes. From the bioclimatic point of view, this area falls in the meso-Mediterranean belt with sub-humid ombrotype. The thorny orophylous shrub vegetation is circumscribed to this cacuminal habitat. No data on these orophilous communities are reported on literature. •

Chios Island
The island, separated from Turkey by the Çeşme Strait, is prevalently mountainous with numerous peaks occuring mainly in the northern part. The largest of these mountains are Mt. Pelineon (1297 m), Mt. Epos (1188 m), Mt. Oros (1186 m), M. Plakes (912 m), and M. Marathovouno (796 m), which show markedly rocky surfaces, often very sloped and rugged. The substrata are prevalently constituted by Mesozoic limestones or more rarely by schists. The mountain area is affected by a meso-Mediterranean sub-humid bioclimate. The cacuminal stands are usually colonized by orophilous dwarf shrubs communities. No data on these orophilous communities are reported on literature.

• Thassos Island
This island is the northernmost of the Aegean Sea, in front of Kavala (N-Greece). The highest peak of Thassos is Mt. Ipsario (1208 m), characterized by schists and Mesozoic marbles. This territory is affected by meso-Mediterranean sub-humid bioclimate. The orophilous thorny shrub vegetation is exclusively localized on limestone outcrops. No data on these orophilous communities are reported in the literature.

Geology
The mountains of central and southern Greece with peaks topping 1700 m are found mainly in Sterea Ellas at the north of Corinth Gulf and in Peloponnese. They are represented mainly by carbonate mountain ranges, characterized by numerous peaks with variable altitudes, many of them reaching 2000 m. As regards the islands, apart from Crete that is not treated in this work, only those reaching altitudes above 900-1000 m have been surveyed by the authors. In particular, among them there are the islands of Cephalonia, Lefkas, Euboea, Samos, Lesbos, Chios, and Thassos, which are characterized by orophilous dwarf shrub communities in the summit of their mountains.
According to literature data [60][61][62], the investigated mountains are geologically constituted in the highest parts by limestones and dolomites dating back to the Mesozoic, or more rarely carbonatic rocks of the Miocene. In some islands, the cacuminal stands are charaterized by outcrops of marbles and schists dating back to the Mesozoic or Paleozoic.
Based on our personal observations in the field, due to the marked erosion, the soils are generally very shallow, accumulating mainly in the cracks and crevices of the rock, as well as in the small depressions or dolines. In the less inclined or often flat stands, the soils show usually a scarce maturity and are mixed with a rich skeletal component, often quite coarse. In these mountains, the screes are also quite frequent, especially in the highest parts, consisting of clasts with varying granulometry that are originated from gelifluxion phenomena in correspondence of the highest peaks or at the base of the cliffs, for the fragmentation of overlying rocky walls.

Bioclimate
According to the classification proposed by Rivas-Martínez [63], Rivas-Martínez and Rivas-Saenz [64] and Rivas-Martínez et al. [65,66], the bioclimate affecting the investigated Greek mountains falls, limited to the highest stands, in the Temperate oceanic sub-Mediterranean one, while as concerns the lower ones in the Mediterranean oceanic pluviseasonal one. Regarding the thermotypes, they ranged in the first case between the supra-temperate and oro-temperate belts limitedly to the sub-Mediterranean variant. At altitudes below to 1500-1600 m, the territories are affected essentially by the meso-or supra-Mediterranean thermotype. On the most southern mountains of Peloponnese and islands, the bioclimate tends to assume connotations more markedly Mediterranean, with thermotypes referring to supra-and oro-Mediterranean in the highest peaks, and meso-Mediterranean in low altitude ones. In particular, on the mountains localized in the islands of the eastern and northern Aegean, the thermotypes fall almost exclusively in the meso-Mediterranean termotype. With regard to rainfall, the tops of the mountain ranges of these regions are affected by ombrotypes between the upper sub-humid one and the upper humid one, tending in the slopes most exposed to moist marine winds, towards the hiper-humid. In fact, the cacuminal stands, and those at altitudes usually above 1600-1700 m, are characterized by rather moist and cold winters, with more or less long periods of snow cover, while the summers are quite hot and dry. Throughout the year, these areas are normally affected by strong winds, as well as by extreme daily temperature ranges and fog regimes.
Just as an example, the charts built according to the scheme proposed by Walter and Leith [67] are provided, using the interpolated data published by Hijmans et al. [68,69], which are listed in the "Global climate surfaces" and relate to the period 1950-2000. These data have been taken from a map grid of 10 km 2 , in which the toponym is not given but only the geographical coordinates of the centroid of the square (Figure 2). Plants 2020, 9, x FOR PEER REVIEW 11 of 147 Figure 2. Climograms of 15 thermo-pluviometric stations of some continental and insular mountains from Greece, obtained from data interpolated by WorldClim according to [68,69].

Floristic Considerations
The floristic set, involved in the orophilous pulvinate vegetation occurring in the mountains of central and southern Greece, as well as some Ionian (Lefkas and Cephalonia) and Aegean islands Figure 2. Climograms of 15 thermo-pluviometric stations of some continental and insular mountains from Greece, obtained from data interpolated by WorldClim according to [68,69]. ( Notes: According to Širjaev [79] the two subspecies differ from the type in some morphological characteristics. In particular, the subsp. euboicus differs in having leaflets denser, outspread white-villous, calyx with short teeth, and corolla 11 mm long, while the subsp. taygeticus apart from having leaflets denser outspread white-villous, is differentiated by a calyx with longer teeth, and corolla 13 mm long. (3) Allium hirtovaginatum subsp. samium Brullo, Pavone & Salmeri, subsp. nov.
Etymology: From the Greek words "cremnos" = crevice and "philos" = fond of, in reference with its habitat.
Distribution: At present, this species seems confined to the top of Mt. Profitis Ilias, the highest summit of Kyllini massif in N Peloponnese (Greece). It is quite rare and occurs in the orophilous dwarf-shrub communities with Astragalus rumelicus subsp. taygeticus on Mesozoic limestone, at 2200-2400 m of altitude.

Phytogeographical Analisys
Regarding the life forms (Table 1), this florula is characterized mainly by hemicryptophytes (H) (43.06%), followed by chamaephytes (Ch) (34.86%), while geophytes (G) (9.78%) and therophytes (T) (9.15%) are clearly inferior. Finally, nanopharenophytes (NP) (2.68%) and phanerophytes (P) (0.47%) are negligible. In fact, due to the extremely harsh conditions of these high mountain habitats, only plants with particular structural adaptations can aggregate in plant communities able to express their potential to the fullest. In this respect, the hemicryptophytes and chamephytes, being perennial plants characterized by a habit slightly raised from the soil, are those that are best suited to these environments. They are affected by a climate with very cold winter, characterized by long periods of snow cover, strong winds blowing on the mountain tops, the marked daily temperature ranges, hot and dry summers. In particular, these habitats are characterized by the dominance of dwarf shrub chamaephytes, showing often a pulvinate habit that tolerates better these extreme environmental conditions. Instead, nanopharenophytes and phanerophytes do not go beyond the timberline, while geophytes and therophytes, having no adaptions, are very rare and grow usually into the shrubs. Table 1. Life forms of the investigated orophilous flora (from [70][71][72][73][74][75][76][77] From the chorological viewpoint, being Mediterranean mountains, the floristic set featuring these habitats, shows a clear predominance of Mediterranean species (Table 2). In particular, the Mediterranean element shows the highest percentage (42.43%), within which the more representative are the East-Mediterranean taxa (29.65%), while the circum-mediterranean ones present lower percentages (9.62%). As concerns the other mediterranean elements, they are scarcely represented. Apart to the Mediterranean element, the endemic one is very high represented (40.38%). Table 2. Chorotypes of the investigated orophilous flora (from [70][71][72][73][74][75][76][77] Within the endemic set, different endemisms can be distinguished, such as: Balkan one which is the more frequent (22.66%), CS Greece one (18.75%), Peloponnese one (17.58%), Greece one (15.23%), Sterea Ellas one (6.25%), while the other endemic species occuring in the Greek islands show a lower percentage, such as those ones of E-Aegean islands (5.86%), Ionian islands (2.73%), N-Aegean (2.73%), and Euboea (2.34%) ( Table 3). Other elements are less significant, such as the European one (11.67%) and the wide distribution one (5.52%), the latter including circumboreal, cosmopolite, and paleotemperate species (Table 2). clear information from an ecological and phytogeographical point of view. Based on the above, these alliances do not satisfy the prerequisites required by the sigmatist phytosociological method. They only create a lot of confusion and ambiguity in the syntaxonomical arrangement of this very peculiar kind of orophilous vegetation. In conclusion, these alliances are really ambiguous names that must be rejected (art. 36). Therefore, a new phytosociological framework is necessary to propose. The designation of new alliances must be essentially based on the phytogeographic criteria and such characteristics must include steno-endemic species in order to define unequivocally the geographical boundaries of each syntaxon as well as its syntaxonomical role. In order to emphasize the distribution of characteristic species within the three alliances and syntaxa of higher rank according to the hierarchic arrangement proposed by Quézel [35], a synoptic table (Appendix B, Table A2) was processed including all the phytosociological relevés published until now on this type of orophilous vegetation in central-southern Greece by Quézel [35,38] and Quézel and Katrabassa [40], as well as other later authors as Georgiadis and Dimopoulos [42] and Maroulis and Georgiadis [44]. From the analysis of this table, the floristic comparison among the hitherto recognized associations, which are well differentiated from the phytosociological viewpoint, shows clearly that the species proposed as characteristics of the alliances are distributed indifferently in all three syntaxa, often with high frequency values. Therefore, it can be easily deduced that a single association cannot be clearly and unambiguously attributed to a specific alliance. Quézel [35] in order to attribute an association to a given alliance, he relied mainly on its altitudinal distribution, rather than considering the information relating to its floristic cortege. Unfortunately, the species selected by the author to define these alliances are not strictly linked to well-defined altitudinal bands, but are widespread almost at all altitudes. From this, it can easily be deduced that, in the case of the orophilous pulvinate vegetation of the Greek mountains, as well as of other geographic territories, this criterion can not be followed. Instead, a purely phytogeographical method must be selected, mainly based on endemic flora, that gives more significant information under phytosociological feature.
On the basis of several unpublished phytosociological relevés carried out by us in the summit stands of most of central and southern Greek mountains as well as in some islands (Figure 1), it was possible to verify that only a strictly phytogeographic policy can allow for a correct syntaxonomic arrangement of these communities, similar to what has been achieved for other Mediterranean territories . In fact, it is much more realistic and meaningful to identify alliances based on floristic elements that give clear information on phytogeographic correlations of the various associations, rather than on their altitudinal distribution. In particular, the flora characterizing the orophilous community usually shows a significant richness in relict species, often very isolated, or represented by geographical vicariants of remarkable phytosociological significance. Therefore, for a syntaxonomic arrangement that can best express the floristic and structural organization of the pulvinate-orophilous plant communities currently occurring in the Greek mountains, it has to be based on the choice of species suitable for providing more precise information on their phytogeographical role. Following this viewpoint, this study presents a clearer and more comprehensive syntaxonomical overview of these plant communities, reflecting their origin and diversification. Therefore, for a correct floristic characterization of higher syntaxa (alliances, orders and classes) allowing differentiation of specific alliances, the choice should fall on endemics with restricted distribution, such as those confined to one or few neighbouring or close mountain ranges, and it should gradually move on to those endemics with wider ranges and the other more widespread taxa which should be used for the designation of orders and classes. In addition, the floristic contingent that differentiates the higher syntaxa, and particularly in the case of orophilous vegetation featuring the Mediterranean mountains, provides clearer information about the relationships that the plant communities show among them, since they are the result of paleogeographic vicissitudes of the territories that host them.
Furthermore, it must be emphasized that Quézel et al. [80] when lectotypified the class Daphno-Festucetea and the corresponding order Daphno-Festucetalia, corrected respectively the two names in Daphno oleoidis-Festucetea variae and Daphno oleoidis-Festucetalia variae. The use of Daphne oleoides and Festuca varia for giving the name to the two syntaxa brings further confusion and ambiguity, since both species are not pertinent to this type of vegetation. In fact, Daphne oleoides is widespread in all Mediterranean mountains and is considered a typical characteristic species of the class Junipero-Pinetea sylvestris Rivas-Martínez 1964, as emphasized by Rivas-Martínez [52], Rivas-Martínez et al. [53][54][55][80][81][82], Stanisci [56] and Brullo et al. [57], while in the pulvinate dwarf shrub vegetation it is rather rare and occasional. As concerns Festuca varia, this species has a properly alpine distribution and is totally absent in Greece [83], where it is replaced by various other species of this genus. Moreover, it is not possible to identify in a univocal and correct way what is the species of Festuca to which Quézel [35] refers in naming these syntaxa.
Besides, among the species proposed by Quézel [35] as characteristic of the class and order is to be noted that some of them, such as Juniperus communis var. hemisphaerica, Berberis cretica, Prunus prostrata and mainly Daphne oleoides, are linked to the orophilous communities characterized by phanerophytes and nanophanerophytes belonging to the class Junipero-Pinetea sylvestris Rivas-Martínez 1965 nom. invers. propos. (=Pino-Juniperetea Rivas-Martínez 1965). This is in agreement with the literature data concerning this type of orophilous forest vegetation [55][56][57]63,84].
In particular as emphasized by Brullo et al. [57] and Mucina et al. [84], the woody communities characterized by the dominance of erect or prostrate conifers occurring in Greece and other central-eastern Mediterranenan territories, must be ascribed to syntaxa exclusive to these mountaints, Besides as emphasized by Brullo et al. [57], some associations of Daphno-Festucetea described by the previous authors must be rather clearly attributed to the class Junipero-Pinetea sylvestris, since they show a floristic, structural and ecological feature of the last syntaxon. In particular, this is the case of the "ass. à Galium lucidum et Ribes uva-crispa Quézel 1964", "ass. à Juniperus foetidissima et Onobrychis ebenoides var. minor Quézel 1973", "Juniperetum foetidissimae Georgiadis & Dimopoulos 1993", "Acer monspessulano-Prunetum mahaleb Georgiadis & Dimopoulos 1993", contributing further to confer a marked ambiguity to the class Daphno-Festucetea.
For the reasons above mentioned, the names Daphno-Festucetea Quézel 1964 and Daphno-Festucetalia Quézel 1964 must be proposed as nomina ambigua rejicienda (Art. 36), since they are based on very ambiguous alliances, are sources of continuous errors in the univocal and unambiguous designation of the relative associations. The new names proposed here in order to replace those of the two aforesaid syntaxa are Cerastio candidissimi-Astragaletea rumelici and Eryngio multifidi-Armerietalia orphanidis, both having a large distribution in the high mountains of southern Balkans and Aegean area.
The floristic analysis of the investigated plant communities occurring mainly in the high mountains of the Peloponnese and Sterea Ellas, as well as in some Ionian Islands and Euboea, showed the existence of significant sets of endemic species, which have a well-defined geographical distribution that allows the identification of alliances based on a clear phytogeographical role, emphasizing especially the palaeogeographical isolation of the various mountain areas among them.
Based on these criteria, it was possible to distinguish in the aforesaid territories some new alliances, which are well circumscribed from the phytogeographical point of view and allow a very realistic arrangement of the orophilous dwarf shrubby vegetation occurring in these Greek high mountains, emphasizing their floristic affinities. These are: Marrubio velutini-Thymion parnassici, distributed in the mountains of Sterea Hellas and Attica; Festuco achaicae-Marrubion cyllenei, from the North Peloponnese mountains; Sideritido clandestinae-Asperulion mungieri, from South Peloponnese mountains. Moreover, Astragalion cephalonici, from the Ionian islands of Cephalonia and Lefkada, as well as Astragalion euboici from the island of Euboea, must be added to these alliances.
In order to highlight that these alliances have a clear phytosociological role with a well-defined phytogeographic boundary than those proposed by Quézel [35], the associations examined in Appendix B, Table A2 were processed according to this new syntaxonomic scheme. As can be clearly observed in the new Table A3 (Appendix B), the associations fall within floristically well-differentiated alliances, since they are characterized by endemics exclusive of geographically distinct areas, which are characterized by very similar paleogeographic vicissitudes.
In addition, further phytosociological investigations were carried out in the high mountains of some islands of North Aegean area (Thassos, Lesbos, Chios, and Samos) peaking over 1000 m. a.s.l and hosting this kind of vegetation. Within the orophilous pulvinate dwarf shrubs communities occurring in these islands, some characteristic species of Cerastio candidissimi-Astragaletea rumelici class are still present (although numerically reduced), while species belonging to the Eryngio multifidi-Armerietalia orphanidis order and related alliances are fully missing.

Stipeto-Morinion
Structure and ecology: Within the order Eryngio multifidi-Armerietalia orphanidis, this alliance is that one showing more marked characters of continentality. The associations belonging to this syntaxon seem to have greater floristic structural and ecological correlations with those ones occurring in the northern Greece. Clearly, towards to the north of Greece, the bioclimate becomes markedly more mesic with a progressive decrease of its Mediterranean character. This is reflected quite well in the orophilic pulvinate vegetation, which shows a more marked thermophily in the mountains of southern Greece. Therefore, this syntaxon can be considered as the transition term between the southernmost alliances occurring in the Peloponnese and probably the northernmost ones regarding the mountain ranges of Pindus and Mt. Olympus, which is still to be defined under the phytosociological profile including several associations already defined by Quézel [36]. In particular, the associations falling in the Marrubio velutini-Thymion parnassici, while maintaining structurally their prerogatives of shrub-pulvinate community, tend to show a certain increase of the hemicriptophytic component. Further, their floristic settlement increases with elements having more relantionships with taxonomic groups having a more northernmost distribution.
Distribution: The alliance is distributed mainly in the massifs of Sterea Ellas, such as Mt. Parnassus, Mt. Giona, Mt. Vardoussia and Mt. Timfristos, as well as of Attica. Probably, plant communities belonging to this syntaxon occur also in other mountains of this continental area of Greece.
Notes: The Marrubio velutini-Thymion parnassici does not show any clear floristic, ecological and chorological correlation with the three alliances described by Quézel [35]. In particular, this new syntaxon is floristically differentiated by endemics distributed in the high-mountain belt of the massifs located exclusively in Sterea Ellas and Attica. In addition, this alliance groups associations that are not linked to a well-defined altitudinal belt, but they are distributed from the lower mountain zones (1200-1300 m) up to the high-mountain ones reaching the altitude of 2500 m.
Syn.: Association à Astragalus creticus subsp. rumelicus et Marrubium velutinum, Quézel 1964. Lectotypus: Table 18, rel. 3, Quézel [35], hoc loco. Characteristic species: Astragalus rumelicus subsp. rumelicus, A. hellenicus, Nepeta parnassica. Structure and ecology: The association is located on calcareous and dolomitic substrata, of more or less rocky steep slopes (30 • -40 • ), characterized by eroded or not very deep soils, rich in coarse skeletal component. It assumes a clear climatophilous role in the supra-temperate sub-Mediterranean belt at an elevation of 1800 and 2100 m, while at lower altitudes (examples were found up to 1500 m) shows a clearly secondary pattern, because its spread is linked to the processes of forest degradation, here represented mainly by Abies cephalonica woods. Physiognomically, this association is dominated by thorny cushion-like of Astragalus rumelicus subsp. rumelicus, which often constitues dense populations. Quite significant it is the occurrence, although scattered, in this vegetation of two interesting endemic species, such as Nepeta parnassica, distributed in Mt. Parnassus and Mt. Chelmos (on the latter, however, is quite rare), and Astragalus hellenicus, widespread on the mountains of Sterea Ellas. Within this association, as emphatized by Quézel [35], two subassociations linked to different soil conditions can be distinguished. They are cited by that author as subass. typicum, localized on carbonatic substrates with no floristic differentiation, and subass. achilleetosum nobilis Quézel 1964 (lectotypus rel. 12, Table 18, Quézel [35], hoc loco) restricted to sandstone or sometimes schist outcrops, differentiated by Achillea nobilis and Salvia argentea var. alpina.
Distribution: This association is well represented on the southernmost massifs of Sterea Ellas, as Mt. Parnassus, Mt. Giona and Mt. Vardoussia. However, its occurrence also in other mountain massifs of this area can not be excluded.
Syn.: Association à Convolvulus cochlearis et Astragalus lacteus Quézel 1964. Lectotypus: Table 21, rel. 4, Quézel [35], hoc loco. Characteristic species: Astragalus lacteus, Convolvulus cochlearis, Koeleria carniolica. Structure and ecology: The association is confined to the dolomitic substrates of the ridges that bordered some deep dolines. The surfaces occupied by this association are usually almost flat and are distributed at an altitude of 1650-1800 m, within the supratemperate sub-Mediterranean bioclimatic belt. This vegetation is dominated by small prostrate chamaephytes, among them have a quite significant role Convolvulus cochlearis (=C. parnassicus Boiss. & Orph.), rather rare Balkan endemic. In this association it occurs also Astragalus lacteus, which shows a quite constant frequence, as well as Asperula rigidula and Koeleria carniolica, which are less frequent.
Distribution: Currently it is known only to the Mt. Parnassus, where it is observed near the refuge of the EOS Gherondovrachos.
Notes: As concerns this association, Quézel [35] highlight that it occupies an intermediate position between the Astragalo-Seslerion and Stipo-Morinion alliances, because in its floristic settlement are present characteristic species of both syntaxa. However, the author considers more properly to include it in the Astragalo-Seslerion, mainly for the occurrence of Astragalus angustifolius. That is further evidence of the lack of phytosociological value of the alliances proposed by the author.
Nepeto epiroticae-Astragaletum corynthiaci (Quézel 1964 [35], hoc loco. Characteristic species: Astragalus corynthiacus, Nepeta nuda var. epirotica. Structure and ecology: The association is localized on the bottom of dolines and also on slightly inclined surfaces characterized by rather deep silt-clay soils, deposited on carbonate substrata. It is distributed between 1600 and 1900 m of altitude, sometimes reaching 2100 m, having its optimum in the supratemperate sub-Mediterranean belt. Physiognomically, this vegetation is differentiated by the dominance of Astragalus corynthiacus, a new species closely related to A. cephalonicus, which tends to constitute dense and homogeneous populations. Another quite significant species is Nepeta nuda var. epirotica, which seems to have its optimum in these stands. Potentially, this association is linked to the erosion processes and washing away of calcareous rocks that accumulate fine particles into the lower parts of dolines and depressions. These surfaces, in extreme conditions, with very deep soils, are ususally colonized by hemicryptophytic communities of Trifolion parnassi. In fact, in this association, some elements belonging to the latter alliance and related order, Trifolietalia parnassi, are present which clearly have the meaning of transgressiion. In conditions of marked edaphic xericity, such as in the stands with rocky outcrops and superficial soils, the vegetation at issue is replaced by the climatophylous communities of Marrubio velutini-Astragaletum rumelici.
Distribution: The association was currently observed only on Mt. Parnassus, where it is represented mainly in the dolines.
Notes: As regards its phytosociological arrangement, this association was described by Quézel [35] as Association à Astragalus cephalonicus et Nepeta nuda and included into the alliance Trifolion parnassi, since the author based on its ecological requirements, being linked to deep soils and on the presence of a fair number of species characteristic of this syntaxon. However, it should be noted that the author considered this association structurally very similar to the communities of Daphno-Festucetalia, especially for the dominance of torny cushion-like shrubs, completely absent in the typical grasslands of Trifolion parnassi. Moreover, for the presence of a significant settlement of Daphno-Festucetalia, he considered this association as intermediate between this order and that of Trifolietalia parnassi. In fact, this perplexity of Quézel [35] is here shared by us too, but basing on its floristic and structural characterics, it seems to exclude its possible attribution to Trifolion parnassi. It is to underline that on the whole in this association are well represented many species of Marrubio velutini-Thymion parnassici and related higher syntaxa. The dominant species was previously identified by Quézel [35] as Astragalus cephalonicus, but this attribution was wrong, since it clearly differs from the latter in numerous morphological features and should be treated as a distinct new species named A. corinthiacus.
Holotypus: Appendix C, Structure and ecology: This association, characterized by dominance of small chamaephytes showing a prostrate or creeping habit, is localized in correspondence to the very windy ridges, usually over 2000 m of altitude. It is possible to observe this vegetation also at lower altitudes (ca. 1800 m), always in cacuminal stands. From the bioclimatic point of view, this association is well represented in the oro-temperate sub-Mediterranean belt extending downward in the supra-temperate sub-Mediterranean one. The surfaces are rather flat with superficial soils rich in minute skeleton, where, due to the action of the winds, the soil evolution is very slow, and the vegetation always keeps a prostrate habit. According to Quézel [35], this vegetation is dominated by plants showing a small size, such as Paronychia polygonifolia (as P. chionaea), Thymus parnassicus (as T. hirsutus subsp. ciliato-pubescens), Edraianthus graminifolius f. minor, Dianthus ventricosus. The pulvinated camaephytes and the cespitose grasses are totally absent. The author distinguished two subassociations linked to altitudinal factors, represented at over 2100 m of altitude by the subass. typicum, which is replaced at lower altitudes from subass. linetosum angustifolii Quézel 1964 (lectotypus : Table 23 rel. 5, hoc loco). Floristically, the first subassociation is differentiated by Euphrasia salisburgensis, Minuartia condensata, Festuca halleri subsp. riloensis, Carex kitaibeliana, and Galium plebeium, while the second one has as differential species Linum tenuifolium and Ptilotrichum rupestre.
Distribution: The association seems to be exclusive of Mt. Giona, where it is very frequent.
Characteristic species: Astragalus tymphresteus. Structure and ecology: The association was observed in stands at altitudes between 1200 and 1400 m, on slightly inclinated slopes characterized by carbonate rocks within the meso-Mediterranean bioclimatic belt. The soils are poorly developed with many minute skeletons. This vegetation is dominated by Astragalus thymphresteus, thorny dwarf shrub growing with other small chamaephytes, such as Nepeta spruneri, Thymus chaubardii, Chamaecytisus hirsutus, and some cespitose hemicryptophytes.
Distribution: The association was found only on Mt. Giona, where it is circumscribed to stands of lower altitudes, but it probably occurs also in other mountains.
Violo stojanowii-Seslerietum vaginalis Quézel 1973, Biol. Gallo-Hellen. 5 Structure and ecology: The association colonizes the rocky outcrops and the stabilized screes at altitudes over 2100 m, within the oro-temperate sub-Mediterranean bioclimatic belt. It is frequent on the prevalently rocky surfaces that, due to the considerable acclivity, the soils are very superficial, accumulating mainly among the rocky crevices and into the bushes. Physiognomically, it is distinguished by the dominance of compact and often voluminous cushion-like shrubs of Minuartia stellata, that usually grows togheter with Sesleria vaginalis and several species with prostrate habit. The characteristic species of the alliance Marrubio velutini-Thymion parnassici are well represented, among them Erysimum parnassi, Marrubium velutinum, Satureja parnassica, which show high coverage value. Within this association Quézel [35] distinguished two subassociations on phytogeographical base, represented by saturejetosum parnassicae (=subass. teucrioides à Thymus), restricted to Mt. Parnassus, and by aurinietosum giónae (=subass. kionae à Alyssum) for Mt. Giona. The first one corresponds clearly to the type, while the second one must be treated as a distinct association, well differentiated from floristically, also from chorological point of view, named as Aurinio gionae-Minuartietum stellatae.
Distribution: Actually, this vegetation is distributed only on Mt. Parnassus.
Distribution: As the two previous associations, this vegetation was surveyed in the same area of Mt. Giona, but at lower altitudes.
Holotypus: Appendix C, Structure and ecology: The alliance replaces in the Ionian islands of Cephalonia and Lefkada the Marrubio velutini-Thymion parnassici distributed in Sterea Ellas and Attica. The syntaxon at issue is well differentiated from the previous alliance for some floristic and ecological peculiarity due to its geographical isolation. Floristically, it is also differentiated by some insular endemics exclusive of Cephalonia and Lefkada, taxonomically quite significant, such as Astragalus cephalonicus, Centaurea subciliaris subsp. subciliaris, Thymus holosericeus, Scutellaria rupestris subsp. cephalonica, and Petrorhagia fasciculata var. cephallenica. The communities belonging to this alliance are localized on the top of isolated mountain summits at altitudes between 800 and 1400 m, which are markedly affected by moist marine winds.
Distribution: The alliance seems circumscribed to the Ionian Islands of Cephalonia and Lefkada.
Structure and ecology: The association is localized on the cacuminal plateau more or less windy, characterized by very rocky calcareous substrata with immature soils. This vegetation has its optimum at 800-1000 m of altitude, within the upper meso-Mediterranean belt. Floristically, it is differentiated by the dominance of the endemic Thymus holosericeus which grows togheter with the tuffs of Helictotrichon convolutum subsp. convolutum, an Est-Mediterranean species, and the endemic Allium lefkadensis. In this association occurs also Astragalus cephalonicus which was already recorded in this mountain by Hofmann [85].
Distribution: This association is localized in the Lefkas Island in small places on Mt. Elati (Stravoti).
Holotypus: Appendix C, Table A27, rel. 6, hoc loco. Characteristic species: Allium cephalonicum, Centaurea spruneri subsp. guicciardi, Satureja cuneifolia. Structure and ecology: The association, ecologically very similar to the previous one, occurs on calcareous rocky outcrops at 800-1000 m of altitude in the Cephalonia Island. Floristically, it is differentiated from the previous one for the lack of Helictotrichon convolutum subsp. convolutum, while Satureja cuneifolia is frequent, which togheter with Thymus holosericeus and Astragalus cephalonicus, characterizes this cushion-like prostrate vegetation. Moreiover, the occurrence of Allium cephalonicum in this vegetation is significant, as a very rare and isolated endemic species, closely related to A. callidictyon C. A. Meyer ex Kunth [86].
Distribution: It is a geographical vicariant of the previous association in Cephalonia Island where it is localized on Mt. Ainos and Mt. Roudhi in open and windy places.
Holotypus: Appendix C, Table A27, rel. 12, hoc loco. Characteristic species: Astragalus cephalonicus, Galium ionicum, Erysimum cephalonicum. Structure and ecology: This association replaces the previous one in the higher stands at altitudes between 1200 and 1400 m, where it is localized in more or less sloping stands characterized by calcareous rocky substrata. Floristically, it is differentiated from the previous association for the dominace of Astragalus cephalonicus which grows togheter with other endemisms as Erysimum cephalonicum and Scutellaria rupestris subsp. cephalonica. This vegetation is localized within supra-Mediterranean bioclimatic belt in the clearing of the Abies cephalonica woodlands that occur in the surfaces with more deep and mature soils.
Distribution: The association occuring in the Cephalonia Island, replaces at higher altitudes the Saturejo cuneifoliae-Thymetum holosericei.
Structure and ecology: This association is localized in cacuminal open stands at an altitude of 1600 m, colonizing the calcareous rocks of southern slopes usually quite inclined. These surfaces are strongly affected by winds and daily thermic changes, also subject to long periods of snow cover, with very superficial and eroded soils. Physiognomically it is characterized by small and flattened pulvines of Astragalus angustifolius subsp. erinaceus, growing together with other dwarf orophytes with chamaephytic or hemicryptophytic habit, some of them endemic, such as Paronychia albanica subsp. graeca, Galium circae, Viola cephalonica, Scutellaria rupestris subsp. cephalonica, etc. This vegetation occurs within supra-Mediterranean bioclimatic belt, which is replaced in the northern slopes with not eroded and mature soils by Abies cephalonica woodlands.
Distribution: The association is exclusive of Cephalonia Island it only occurs in the top of Mount Ainos. Structure and ecology: The alliance can be considered a geographical vicariant on the Euboea mountains of the Marrubio velutini-Thymion parnassici distributed in the continental Central Greece. It is differentiated from the latter alliance for its floristic peculiarities (represented by several endemics), linked to geographical isolation due to its insularity. The plant communities belonging to this syntaxon are surveyed at altitudes between 1000 and 1700 m on prevalently carbonatic substrata.

ASTRAGALION EUBOICI
Distribution: The alliance is circumscribed to the Euboea Island in the Central Egean Sea.
Sideritido euboeae-Astragaletum euboici Musarella, Brullo & Giusso ass. nov. hoc loco (Appendix C, Table A28). Structure and ecology: This alliance represents the southern geographical vicarious of Marrubio velutini-Thymion parnassici, grouping, similarly to the latter, orophilous plant communities structurally characterized by the dominance of chamaephytes and pulvinate nanophanerophytes, sometimes mixed with caespitose hemicryptophytes. Particularly, they differ from those ones occurring in the mountains of Sterea Ellas, apart from the occurrence of a rich set of endemics, also for their ecological requirements. In fact, these communities are subject to climatic conditions characterized by a a more marked thermophily, with higher average annual temperatures and drier rainfall regime, especially in summer. This area falls mainly in the supra-and oro-temperate of sub-Mediterranean type. Moreover, from the phytogeographical point of view, it is possible observe a strong increase of species belonging to taxonomic groups showing a more southern origin.
Notes: The Festuco achaicae-Marrubion cyllenei has a strictly phytogeographical characterization, since it is floristically differentiated by species confined to the mountains of Achaia, Corinthia and North Arcadia. It groups plant communities occurring in high mountain stands at altitudes from 1200 to 2400 m. This alliance groups, in addition to several new associations, also other ones described by Quézel [35], Quézel and Katrabassa [40], Georgiadis and Dimopoulos [42], Maroulis and Georgiadis [44], which previously were attributed by these authors in the alliances Stipo-Morinion, Eryngio-Bromion and Astragalus-Seslerion.
Cirsio hypopsilii-Astragaletum taygetici Quézel 1964 corr. (Table A32 [44]. Lectotypus: Table 17, rel. 1, Quézel [35], hoc loco. Characteristic species: Astragalus rumelicus subsp. taygeticus, Cirsium hypopsilium. Structure and ecology: The association is localized on the slopes more or less inclined with variable exposure, characterized by carbonatic stony substrata with rocky outcrops. The soils are enough evolved, but with a significant component of coarse skeleton. It is widespread at altitudes from 1400 to 2000 m, within the supra-temperate sub-Mediterranean bioclimatic belt, with penetrations upwoard in the oro-temperate submediterranean belt and downward in the meso.Mediterranean one. In fact, examples of this vegetation can be observed up to 2150 m of altitude in places well exposed and sunny, as well as at relative low altitudes (1150 m), limited to cacuminal and very rocky windy stands. Physiognomically, this association is differentiated by large thorny pulvinate individuals, often quite raised from the ground, of Astragalus rumelicus subsp. taygeticus, that in the Peloponnese replaces the subsp. rumelicus, distributed in the central and northern Greece [87]. Previously, the populations of this Astragalus occurring in the M. Killini were identified by Quézel [35] and Georgiadis and Dimopoulos [42] as Astragalus cylleneus, quite rare species on this massif, where it is localized in habitat totally different from those ones normally occupied by the association in question. As regards the floristic composition of this pulvinate vegetation, it is observed a rich contingent of characteristic species of the alliance, as well as of higher syntaxa. It assumes usually a climatophilous role especially at altitudes over 1700-1800 m, while at lower altitudes can be considered as an edaphophilous vegetation, limitedly to cacuminal more rocky stands. Within the climatophilous belt relative to Abies cephalonica woodlands, the association represents usually a substitution aspect, due to degradation of this forest.
Distribution: The association is widespread and well represented in the various mountains of the northern Peloponnese, as Mt. Erimanthos, Mt. Panachaiko, Mt. Klokos and Mt. Killini, where it tends to occupy large surfaces.
Notes: This association was originally described by Quézel [35] for Mt. Killini as ass. à Astragalus cylleneus et Cirsium cylleneum and successively redescribed by Georgiadis and Dimopoulos [42], but changing its name in Astracantho thracicae-Marrubietum cyllenei comb. nova, not indicating the holotypus. Therefore, the last syntaxon is an invalid name, according to articles 3 c and 5. In both cases, the authors indicate as characteristic species, physiognomically dominant, Astragalus cylleneus (=Astracantha thracica subsp. cyllenea). Unfortunately, this species was misidentified by these authors, since on the Mt. Killini in the stands where they have carried out the relevés there is exclusively Astragalus rumelicus subsp. taygeticus, while the true A. cylleneus is very rare and confined in depressed areas, such as dolines, characterized by very deep soils rich in silt-clay component, not occurring never on rocky substrata. The association occurs with the same ecological characteristics and floristic composition also on Mt. Erimanthos, where it was correctly described by Maroulis and Georgiadis [44] as Marrubio cyllenei-Astragaletum rumelici. However, this syntaxon is an illegitimate name being a synonym of the association described by Quézel [35], whose name must be corrected in Cirsio hypopsilii-Astragaletum taygetici. In this association are well represented the characteristic species of the three alliances proposed by Quézel [35], particularity already evidenced by Georgiadis and Dimopoulos [42] and also by Maroulis and Georgiadis [44].
Syn.: Association à Aster cylleneus et Globularia stygia. Quézel 1964, Vegetatio, 12:337. Lectotypus: Table 20, rel. 5, Quézel [35], hoc loco. Characteristic species: Aster cylleneus, Globularia stygia, Macrotoma cephalotes, Taraxacum bythinicum. Structure and ecology: The association has its best expression between 2000 and 2330 m of altitude, within the orotemperate sub-Mediterranean bioclimatic belt. It can be observed sometimes up to 1800 m in stands representated by rocky ridge. Usually, it is localized on markedly rocky surfaces, constitute by carbonate substrata, as the ridges, saddles and stabilized screes, stends generally very windy with very shallow and undeveloped soils. It is a vegetation dominated by small prostrate dwarf shrubs mixed with several hemicryptophytes. The most important species are Globularia stygia and Aster cylleneus, rare endemics known for Mt. Chelmos and Mt. Killini. Floristically, the association is rather poor with low values of coverage. Dynamically, it can be considered an essentially edaphophilous vegetation.
Distribution: The association is currently known only for Mt. Chelmos and Mt. Killini in the northern Peloponnese.
Notes: This association was previously included by Quézel [35] within Astragalo-Seslerion, even though, as evidenced by the same author, the species of this alliance were not well represented in the relevés.   [40], hoc loco. Characteristic species: Asperula oetaea, Euphrasia salisburgensis, Iberis saxatilis subsp. saxatilis. Structure and ecology: The association is localized at 2000 and 2200 m of altitude in the windy crests, with flat surfaces formed by eroded limestone cracked and free of soil. It is linked to the oro-temperate sub-Mediterranean bioclimatic belt, where it assumes a role clearly edaphophilous. Physiognomically, it is dominated by small prostrate chamaephytes mixed to rosulate hemicryptophytes with coverage values not too high. It is significant the occurrence of some orophytes that find in this vegetation type their optimal growth conditions, such as Asperula oetaea (by Quèzel and Katrabassa [40] quoted as A. nitida), Paronychia albanica subsp. graeca (as P. chionaea), Euphrasia salisburgensis and Iberis saxatilis subsp. saxatilis. These authors distinguish within this association two sub-associations proposed as erodietosum chrysanthi, located on compact limestone, and minuartietosum confusae, occurring on calcareous substrata that flake on plakes.
Distribution: The association occurs only on Mt. Chelmos in northern Peloponnese.
Marrubio cyllenei-Astragaletum calavrytensis Musarella, Brullo & Giusso ass. nov. hoc loco (Appendix C, Table A35). Distribution: On the basis of current knowledge, this association seems to be exclusive of Mt. Chelmos in the northern Peloponnese.
Notes: Previously Quézel and Katrabassa [40] attributed this vegetation to the Ass. à Astragalus cylleneus et Cirsium cylleneum described by Quézel [35] for Mt. Killini. Effectively as previously emphasized, the aforesaid authors mistakenly attributed these populations of A. calavrytensis to A. cylleneus. As clearly can be observed from floristic composition and ecology, the vegetation of Mt Chelmos is well differentiated from that one of Mt. Killini and therefore they must be treated as two distinct associations.
Structure and ecology: The association is localized in small depressions, similar to dolines, in the middle of the carbonatic rock outcrops, where there is a fairly deep soil rich in silt and clay, accumulated as a result of processes of washing away of the surrounding surfaces more or less sloping. It was surveyed in the supra-temperate sub-Mediterranean bioclimatic belt at 1800-2000 m of altitude. Physiognomically, it is dominated by Astragalus cylleneus, usually associated with numerous other orophytes of the alliance and higher syntaxa. The deep and compact soil justifies the occurrence of mesic species of the Trifolion parnassi, such as Alopecurus gerardii, Plantago atrata subsp. graeca and Potentilla recta. The arrangment of this association in the Festuco achaicae-Marrubion cyllenei rather than in the Trifolion parnassi is justified by the fact that from the structural point of view it is a shrub vegetation of tragacanthoid type, as most of the community of the alliance in question and not of a meadow with prevalence of small herbaceous hemicryptophytes. In addition, the floristic contingent of species of the Cerastio candidissimi-Astragaletea rumelici as well as the related alliance is clearly prevalent respect to that one of Trifolietalia and Trifolion parnassi.
Distribution: This association was observed on Mt. Killini, where is localized exclusively on Mt. Simios.
Notes: The Plantagini graecae-Astragaletum cyllenei is floristically and ecologically quite related to the Nepeto epiroticae-Astragaletum corynthiaci occurring on M. Parnassuss. In fact, both associations are characterized by the dominance of vicariant tragacantoidi species of Astragalus and by the occurrence of species of Trifolion parnassi. In addition, they are localized exclusively in stands more or less depressed with very thick and compact soils, poor in skeleton.
Festuco achaicae-Minuartietum stellatae Musarella, Brullo & Giusso ass. nov. hoc loco (Appendix C, Table A37).  Table A37, rel. 7, hoc loco. Characteristic species: Minuartia stellata, Festuca jeanpertii subsp. achaica, Allium cylleneum. Structure and ecology: The association is linked to rocky stands with calcareous outcrops or to compact rocky surfaces, more or less sloping at the foot of vertical walls. It is a habitat of semirupestrian type, with soils present only in rocky crevices or in small ledges. This vegetation seems to have its optimum in the oro-temperate sub-Mediterranean bioclimatic belt, at 2000-2250 m of altitude; examples can be observed also at lower altitudes (up to 1800 m) within the supra-temperate sub-Mediterranean belt. Physiognomically, the association is differentiated by the occurrence of compact and large pulvini of Minuartia stellata, sometimes mixed with smaller other ones of Asperula boissieri. The characteristics of the alliance of higher syntaxa are here well represented; among these show a greater diffusion and coverage Astragalus angustifolius subsp. erinaceus, Festuca janpertii subsp. achaica and Festuca cyllenica subsp. cyllenica. The association is a typical edaphophilous aspect, colonizing small areas scattered in midst of the tragacanthoid community of Cirsio hypopsilii-Astragaletum taygetici or Plantagini graecae-Astragaletum cyllenei. Previously, it was described by Quézel and Katrabassa [40] as. aggr. à Minuartia stellata and by Georgiadis and Dimopoulos (ref. [42] as comm. à Minuartia stellata).
Distribution: This association is well represented on Mt. Chelmos, Mt. Killini and Mt Klokos in the northern Peloponnese.
Structure and ecology: The association is localized on the rocky ridges, sometimes cacuminal, on substrates consisting of compact craked limestone, with soil present only in the rocky ravines and ledges. It was observed at 1900-2350 m of altitude, within the oro-temperate sub-Mediterranean bioclimatic belt, in ecologically very specialized contexts. In fact, in these stands there are very rigid environmental conditions, as strong winds, soil erosion, marked acclivity, gelifluction, etc. This vegetation represents a typical orophilous thinned out grassland, dominated by Sesleria tenerrima. In the middle of the tuffs of this grass grow several hemicryptophytes and chasmophyte, that highlight the semirupestrian characteristics of the habitat. This association clearly constitutes an edaphophilous aspect, replaced in typically rocky habitats by casmophilous comminities of Asplenietea trichomanis.
Distribution: Based on current knowledge, the association is known only for Mt. Chelmos in northern Peloponnese.
Notes: Within this association some relevés carried out by Quézel and Katrabassa [40] and considered by them as a facies à Sesleria caerulans of the subass. à Festuca varia of the ass. Holotypus: Table 3, rel. 1, Georgiadis and Dimopoulos [42], hoc loco. Characteristic species: Festuca cyllenica subsp. cyllenica, Dianthus integer subsp. minutiflorus. Structure and ecology: The association colonizes the rocky calcareous substrata and stabilized screens, more or less sloping with shallow undeveloped and heavily skeletal soils. It is usually distributed at 2000 and 2200 m of altitude, coming down sometimes up to 1800 m, within the oro-temperate sub-Mediterranean bioclimatic belt, penetrating marginally also in that one supra temperate sub-Mediterranean belt. Physiognomically, it is differentiated by the dominance of large tufts of Festuca cyllenica subsp. cyllenica, that, sometimes, are mixed with those ones of Sesleria vaginalis. Scattered with these grasses there are some low prostrate pulvini of Asperula boissieri and Astragalus angustifolius subsp. erinaceus. It usually assumes a climatophilous role in the higher cacuminal places of the mountains.
Distribution: The association is known only for Mt. Killini in the northern Peloponnese. Notes: This association was described by Georgiadis and Dimopoulos [42] from various stands of Mt. Killini and included by them with some perplexity within the Astragalo-Seslerion, due to the occurrence of a relevant number of characteristics of the Eryngio-Bromion. However, this syntaxon is an invalid name, because the authors do not indicate the relevé type of the association.
Holotypus: Appendix C, Structure and ecology: The association is linked to stabilized screes characterized by a marked acclivity and occurrence of undeveloped soils with a high percentage of skeleton. It is located at 2000-2100 m of altitude, within the oro-temperate sub-Mediterranean bioclimatic belt. It is a typical grassland characterized by the dominance of Sesleria tenerrima, showing a very scattered coverage, interspersed with small bare sufaces. Mixed with this grass there are tuffs of Festuca cyllenica subsp. cyllenica, which often show a high coverage, and several quite significant rosulate hemicryptophytes, such as Ranunculus brevifolius, Ranunculus sartorianus, Dianthus serratifolius subsp. abbreviatus. For its peculiar ecology, the association must to be considered as an edaphophilous aspect, which tends due to the natural evolution of the soil, towards pulvinate communities, structurally more evolved.
Distribution: The association occurs only in Killini massif on Mt. Simios (northern Peloponnese).
Structure and ecology: The association is localized along the very sloped surfaces on stabilized screes or rocky stands with undevelopped calcareous soils rich in scheleton. It is widespread at 1750-2200 m of altitude, within the supra-temperate and oro-temperate sub-Mediterranean bioclimatic belts, where it plays a climatophilous role. This vegetation constitutes dense orophilous grasslands dominated by Festuca cyllenica subsp. cyllenica, Festuca polita and Sesleria vaginalis, where are frequent several other hemicryptophytes and small chamaephytes.
Distribution: According to literature, it is widespread on various mountains of the Erimanthos massif in the Northern Peloponnese.
Notes: The association described by Maroulis and Georgiadis [44] as Festuco politae-Festucetum cyllenicae, was included by the authors in the Eryngio-Bromion although there is a significant contingent of characteristics of Astragalo-Seslerion. For its structure and ecology, as well as for its floristic composition, this association is quite related to Asperulo boissieri-Festucetum cyllenicae from Mt. Killini, from which differs mainly for its floristic set.
Structure and ecology: The association occurs mainly on stabilized screes or on quite inclined slopes covered by calcareous stones, mixed with scarce humus. It is surveyed at 1500 and 1600 m of altitude on northern slopes, it colonizes large surfaces. Physiognomically, it is characterized by the dominance of large tufts of Festuca cyllenica subsp. cyllenica, which grows very well on inclined slopes subject to long periods of snow coverage. This vegetation, where it is frequent also Festuca jeanpertii subsp. achaica, results well differentiated from the other associations with Festuca cyllenica subsp. cyllenica for the occurrence of Arenaria filicaulis subsp. filicaulis and Ranunculus psilostachys.
Distribution: The association is frequent on Mt. Panachaiko in the northern Peloponnese.
Holotypus: Appendix C, Table A47, rel. 7, hoc loco. Characteristic species: Festuca cyllenica subsp. cyllenica, Viola graeca, Ornithogalum oligophyllum. Structure and ecology: The association occurs on calcareous stabilized screes and stony slopes at 2000 and 2500 m of altitude. It is a pioneer vegetation linked to slightly inclined surfaces and poor in soil. Physiognomically, it is characterized by the dominance of Festuca cyllenica subsp. cyllenica, which constitute wide grasslands where occur several orophytes of higher syntaxa. Small hemicryptophytes and geophytes found often refuge among the tuffs of this plant, among them Viola graeca, Ornithogalum oligophyllum, Allium frigidum, Galium taygeteum, Geocaryum peloponnesiacum, etc.
Distribution: This association is widespread on Mt. Chelmos.
Holotypus: Appendix C, Table A48, rel. 1, hoc loco. Characteristic species: Helictotrichon convolutum subsp. heldreichii, Tripodion graecum. Structure and ecology: The association occurs at 1400 and 1600 m of altitude, in the large rock clearing within the Abies cephalonica woodlands. Normally it is frequent along the more or less inclined slopes characterized by rocky outcrops with very shallow and immature soils. The occurrence of Tripodion graecum is significant, i.e., since it is a species known only from a few places in the Peloponnese and Anatolia (mainly in the Taurus region). It is usually associated with Helictotrichon convolutum subsp. heldreichii, generally with high values of coverage, and Festuca jeanpertii subsp. achaica. In this vegetation the species of higher syntaxa are overall well represented.
Distribution: The association is widespread in the lower montane belt of Mt. Menalon, Central Peloponnese. Structure and ecology: It gathers, likewise to the previous alliances included in order Eryngio multifidi-Armerietalia orphanidis, the orophilous plant communities rich in chamaephytes and nanophanerophytes, often with pulvinate habit, as well as in hemicryptophytes, while rarer are the geophytes. On the whole, the associations belonging to this alliance show a more marked thermophily than those ones of the other two alliances. In addition, the considerable contingent of endemics that characterizes this syntaxon is represented mainly by species taxonomically quite isolated or otherwise of remarkable phytogeographical significance. From the bioclimatic point of view, this alliance falls in an area affected by termotypes referring to supra-and oro-Mediterranean, since one detects a long period of high summer dryness enough, although there is a certain tendency towards the supra-and oro-temperate sub-Mediterranean type, with ombrotypes characterized by scarce rainfall, especially during the summertime.

SIDERITIDO CLANDESTINAE-ASPERULION MUNGIERI
Distribution: The alliance is confined to the southern Peloponnese including the massifs of the Taygetos and Parnon.
Structure and ecology: The association is located on rocky outcrops or however more or less rocky surfaces consisting of compact limestone subject to heavy erosion and washing away. The soils are very superficial and localized in crevices and ledges. It is widespread within the meso-mediterranean and supra-Mediterranean bioclimatic belt, at 1250-1800 m of altitude. This vegetation is dominated by chamaephytes and nanophanerophytes of small and medium size, mixed to several caespitose hemicryptophytesche, and among them there are Onosma leptantha, Scabiosa taygetea subsp. taygetea, Pterocephalus perennis spp. perennis, Stipa endotricha, Dasypyrum hordeaceum, Koeleria mitrushii, Bromus riparius, Festuca jeanpertii subsp. jeanpertii. The association has a purely edaphophilous role, although it represents a secondary aspect too, as a result of degradation processes of Abies cephalonica woodlands.
Distribution: The association is distributed on Mt. Taygetos in the southern Peloponnese. Notes: This association was considered by Quézel et al. [80] as the nomenclatural type of the alliance Stipo pulcherrimae-Morinion persicae, although in the relative phytosociological table there are several characteristic species of the other two alliances described by Quézel [3].
Holotypus: Appendix C, Table A50, rel. 4, hoc loco. Characteristic species: Fumana paphlagonica subsp. alpina, Danthoniastrum compactum. Structure and ecology: The association is localized on the slightly sloping limestone slabs, especially with an eastern exposure. It is developped within the supra-Mediterranean bioclimatic belt at an altitude of about a 1700 m. The surfaces are free of soil except in the cracks and small depressions, that allow the establishment of a rather sparse vegetation. It is a vegetation rich in small prostrate chamaephytes, sometimes creeping, among them particularly significant are Fumana paphlagonica subsp. alpina, Helianthemum hymettium, Teucrium montanum var. parnassicum and Asperula mungieri. Several hemicryptophytes, such as Danthoniastrum compactum, Festuca jeanpertii subsp. jeanpertii, Koeleria mitrushii and Stipa endotricha are also well represented. This association plays a clearly edaphophilous role replacing the Scabioso taygeteae-Onosmetum leptanthae in the above-mentioned habitats.
Distribution: Basing on the current knowledge, the association is confined to a small area of Mt. Taygetos in the southern Peloponnese.
Sideritido clandestinae-Astragaletum taygetici Musarella, Brullo & Giusso ass. nov. hoc loco (Appendix C, Structure and ecology: The association is widely distributed on flat and sometimes more or less sloped surfaces, characterized by not very deep soils, rich in minute skeletal component of carbonatic nature. It grows at 1700 and 2100 m of altitude, within the supra-Mediterranean bioclimatic belt with penetrations in oro-Mediterranean that one. This vegetation is physiognomically differentiated by the dominance of flashy tragacanthoid pulvini of Astragalus rumelicus subsp. taygeticus, A. taygeteus and, more rarely, by A. angustifolius subsp. erinaceus. Many other small shrubs are also quite frequent, such as Plantago holosteum var. alpestris, Sideritis clandestina subsp. clandestina, Cerastium candidissimum and several hemicryptophytes. Overall, the association, which usually shows a high value of coverage, must be considered as a climatophilous aspect, spread on all slopes regardless of exposure. From the physiognomic-structural point of view, it is quite related with the other pulvinate tragacanthoid associations dominated by Astragalus rumelicus s.l., such as Cirsio hypopsilii-Astragaletum taygetici, Astragaletum lacteo-taygetici and Marrubio velutini-Astragaletum rumelici. Distribution: The association is exclusive of Mt Taygetos, in the southern Peloponnese. Notes: This vegetation was described by Quézel [35] with the name "Association à Sideritis theezans", which actually is not very significant from the floristic-structural viewpoint. In fact, Sideritis theezans (whose correct name is S. clandestina subsp. clandestina) is a small camaephyte with a secondary physiognomically role in the context of this shrubby association, dominated by some tragacanthoid nanophanerophytes, such as Astragalus rumelicus subsp. taygeticus and A. taygeteus. According to art. 29, the syntaxon is an illegitimate name and therefore should be replaced by a new name that expresses in clear way its floristic and physiognomic-structural peculiarities. It is therefore proposed the new name Sideritido clandestinae-Astragaletum taygetici with a better floristic characterization. In this regard it should be noted that S. clandestina subsp. clandestina is not exclusive to this association, but it is an endemic chamaephyte widespread in various orophilous communities of southern Peloponnese and therefore it has been proposed as characteristics of the alliance Sideritido clandestinae-Asperulion mungieri.
Rindero graecae-Acantholimetum graeci Quézel 1964, Vegetatio, 12:336 (Appendix C, Structure and ecology: The association is localized in cacuminal stands of high altitude, about 2200-2400 m, within the oro-Mediterranean bioclimatic belt. It prefers quite acclive surfaces, where it shows a coverage of 40-70%, which decreases significantly at higher altitudes. The substrata are represented by carbonatic rocks that break up into plaquettes or sometimes by semi-stabilized screes. Physiognomically the vegetation is characterized by thorny pulvini of Astragalus angustifolius subsp. erinaceus and Acantholimon graecum, mixed to several caespitose hemicryptophytes, such as Sesleria vaginalis. In addition, it is very significant the occurrence of some rare endemics exclusive of this vegetation, as Jurinea taygetea and Aethionema carlsbergii. This community, showing a clear climatophilous role, is linked to winterproof environmental features, such as the prolonged snow cover, the accentuated phenomena of gelifluction, exposure to cold winds and the occurrence of rocky substrata with shallow and immature soils. The name of this association must be corrected in Rindero graecae-Acantholimetum graeci since Acantholimon echinus subsp. echinus used by Quézel [35] is taxonomically incorrect and should be attributed to Acantholimon graecum (see Dimopoulos et al. [71].
Distribution: The association is confined to the cacuminal higher part of Mt. Taygetos, in the southern Peloponnese.
Notes: This association was included by Quézel [35] in the Astragalo-Seslerion and afterwards indicated by Quézel et al. [80] as the lectotype of this alliance.
Holotypus: Appendix C, Table A53, rel. 3, hoc loco. Characteristic species: Onosma heterophylla. Structure and ecology: The association was surveyed on carbonatic rocky slopes more or less inclined occurring at relatively low altitudes (1300-1500 m), characterized by coarse material mixed with immature soils. It is localized within the meso-Mediterranean bioclimatic belt, usually occupied by Abies cephalonica woodlands. From the physiognomic-structural point of view, this vegetation is differentiated by thorny pulvini of Astragalus angustifolius subsp. erinaceus, that grow together with other shrubs and several caespitose hemicryptophytes; among the latter there are Onosma heterophylla, Stipa endotricha, Festuca jeanpertii subsp. jeanpertii, Koeleria mitrushii, Bromus riparius, Stipa holosericea. It is a substitution community linked to the degradation processes of the woody vegetation, although in strictly rocky conditions it tends to have an edaphophilous role.
Distribution: The association has been surveyed on M. Parnon, exclusively at Prophitis M. Ilias, near Agriani in the Southern Peloponnese.
Notes: This association is closely related to Scabioso taygeteae-Onosmetum leptanthi from Mt. Taygetos, of which it can be considered a geograpical vicariant.
Structure and ecology: The association is linked to rocky slopes characterized by very compact limestone with soil accumulating only in crevices and depressions of the rocks. It is well developed between 1400 and 1800 m of altitude, within the meso-Mediterranean and supra-Mediterranean bioclimatic belts, constituting usually a climatophilous vegetation which tends to expand towards lower elevations as a result of the degration processes of Abies cephalonica forest. This vegetation is physiognomically characterized by tragacanthoid pulvini of Astragalus rumelicus subsp. taygeticus and A. angustifolius subsp. erinaceus, in the midst of which grow several small chamaephytes and caespitose or rosulate hemicryptophytes. Distribution: The association occurs only on the massif of Parnon, in the southern Peloponnese, where it is common in several mountains.
Notes: From the physiognomic-structural and partially floristic viewpoint, this association is quite similar to Sideritido clandestinae-Astragaletum taygetici from Mt. Taygetos, differing, however especially for the dynamic role, since the latter association is distributed in a higher altitudinal belt.
Holotypus: Appendix C, Table A55, rel. 2, hoc loco. Characteristic species: Viola parnonia, Astragalus agraniotii, Centaurea parnonia. Structure and ecology: The association covers the rather inclined rocky slopes characterized by generally undeveloped calcareous soils, sometimes represented by lithosols. It is widespread within the bioclimatic supra-Mediterranean bioclimatic belt at 1700-1900 m of altitude, regardless of exposure. In this community plays a significant physiognomic role Astragalus angustifolius subsp. erinaceus, which tends to constitute with its characteristic compact thorny pulvini extensive populations. Furthermore, the occurrence of several chamaephytes and hemicryptophytes, including in particular some rare endemics such as Viola parnonia, Astragalus agraniotii and Centaurea parnonia, differentiate vey well this vegetation from other ones of this alliance. Based on the edaphic characteristics, it is possible to distinguish two subassociations, indicated as astragaletosum erinacei and asperuletosum malevonensis, which will be examined below.
Distribution: The association was surveyd exclusively on Megali Tourla, which is the highest mountain of the Parnon Massif in the southern Peloponnese.
Holotypus: Appendix C, Table A55, rel. 2, hoc loco. Characteristic species: Astragalus angustifolius subsp. erinaceus (dominant). Structure and ecology: It represents the typical aspect of the association and is localized on the inclined slopes of the summit, where it colonizes surfaces rich in clastic stabilized material with more or less deep and rich in coarse skeleton soils. Physiognomically, it is differentiated by the dominance of Astragalus angustifolius subsp. erinaceus, which tends to cover most of the surface occupied by the association. This subassociation plays a prevalently climatophylous role, although currently it is also widespread in stands in the past occupied by Abies cephalonica forests, where has a secondary meaning as a result of degradation processes of soil.
Distribution: See association.
Holotypus: Appendix C, Structure and ecology: This order groups the orophilous pulvinate plant communities dominated by chamaephytes and nanophanerophytes with tragacanthoid habit linked to cacuminal very sunny and windy stands at altitudes higher than 900-1000 m. The substrates are prevalently carbonatic with immature soils rich in coarse skeleton occurring mainly in the rocky crevices. The vegetation belonging to this syntaxon colonize mainly rocky surfaces more or less denuded, often quite sloping, affected by moist marine winds or a regime of mists. During the winter period these stations are usually covered for quite short periods by snow. On the basis of investigations carried out in the Aegean area, the habitats colonized by this type of vegetation are represented mainly by the summit areas of island mountains, where the peculiar environmental conditions above emphasized can be found. From the bioclimatic point of view, the order is linked to mountain or high mountain habitats falling into mesoand supra-Mediterranean belts, extending marginally also in the oro-Mediterranean one. Floristically, the order is characterized by a rich contingent of species having mainly an East Aegean-Anatolian distribution, including also several rare endemics.
Distribution: Basing on the current knowledge, the order seems distributed on the mountains of some north-eastern Aegean islands, such as Samos, Chios, Lesvos and Thassos. It is likely that plant communities related to this syntaxon are also present on the island of Samothraki, Mt. Athos, and some coastal mountains of western Anatolia.
Notes: The Noaeo mucronatae-Silenetalia urvillei must be considered as the eastern vicariant of Eryngio multifidi-Armerietalia orphanidis, distributed in the mainland of central-southern Greece, as well as in some Ionian Islands and Euboea. Structure and ecology: This alliance gathers the plant communities occurring in cacuminal stands of island mountains, localized at 900-1400 m of altitute. It is an essentially calcicolous syntaxon linked to a meso-Mediterranean bioclimatic belt, extending towards the supra-Mediterranean one. It has its best expression in very peculiar ecological conditions, where some environmental factors play an important role, such as the marine moist winds, rather cold during the autumn and winter, the erosive action of weathering on rocky surfaces, the mists, and the marked summer dryness. Floristically, it is differentiated by a rich endemic and rare species contingent, having a considerable taxonomical and phytogeographical significance.

ASPERULION SAMIAE
Distribution: The alliance is confined to the mountains of the island of Samos in the eastern Aegean.
Holotypus: Appendix C, Table A56, rel. 3, hoc loco. Characteristic species: Astragalus creticus subsp. samius and Allium orosamium. Structure and ecology: The association is localized on calcareous slopes of cacuminal areas at 1000-1400 m of altitude, where it tends to cover wide surfaces. It has its best expression on compact rocky substrates, often very sloping, represented by calcareous outcrops and buttresses, with soils present almost exclusively in the crevices and ledges. From the bioclimatic viewpoint, this vegetation grows within the meso-Mediterranean belt, extending marginally also in the oro-Mediterranean one, showing a role, not strictly climatophilous, but rather of edaphophilous vegetation. However, it is spread in an area located above the limit of the forests, consisting mainly of Pinus brutia and Quercus calliprinos woodlands. In the tracts with deeper and mature soils, this pulvinate vegetation is mixed to relict of orophilous conifer forest of Junipero-Pinetea sylvestris, where Juniperus foetidissima and J. oxycedrus play an important role. Floristically, the association is characterized by the dominance of thorny pulvini of Astragalus creticus subsp. samius, punctiform endemic of considerable phytogeographical interest. Several relevant endemic orophytes, such as Allium orosamium, Alyssum samium, Anthemis samia, Asperula samia, Erodium sibthorpianum. subsp. vetteri, and Thymus samius occur in this association and probably also Centaurea xylobasis, a rare endemic exclusive of these cacuminal stands.
Distribution: The association is exclusive of the cacuminal area of Mt. Kerkis in the island of Samos (East Aegean).
Holotypus: Appendix C, Structure and ecology: The association is localized in a cacuminal area characterized by outcrops of compact crystalline limestone (marble), with surfaces flat or slightly sloping. The soils are very shallow and fill the depressions and cracks of the rock. The area in which it is developed, localized at 1100-1200 m of altitude, falls within the meso-Mediterranean bioclimatic belt. From the structural point of view, it is observed the dominance of low pulvinate or creeping shrubs, among them Astragalus condensatus, tragacanthoid species, playing a relevant role, and various other small shrubs, such as Asperula samia, Noaea mucronata, Satureja spinosa var. glabra, Thymus samius, etc. In this association are found numerous endemic species rather rare exclusive of these cacuminal stands. Outside of the limestone outcrops, in correspondence of the schistose substrata, this pulvinate vegetation is replaced by Pinus pallasiana woodlands, adaphically much more exigent. On the whole, this vegetation has a clear edaphophilous role.
Distribution: The association is exclusive of cacuminal area of Mt. Ambelos in the island of Samos (East Aegean).
Notes: The Thymo samii-Astragaletum condensatis can be considered a vicariant of the Astragaletum samii, occurring on different substrata in another mountain of Samos.
Holotypus: Table 11, rel. 5, Christodoulakis and Georgiadis [41], hoc loco. Characteristic species: Genista parnassica, Campanula lyrata subsp. lyrata. Structure and ecology: Based on the relevés published by Christodoulakis and Georgiadis [41], at altitude lower than 1000 m always in calcareous rocky stands, more or less sloping, the Astragaletum samii is replaced by another type of shrub pulvinate vegetation, differentiated by the dominance of Genista parnassica. In the places occupied by this vegetation, Astragalus creticus subsp. samius is wholly absent, as well as the species most significant of the alliance and order decrease and become quite rare. This community, which is proposed as Campanulo lyratae-Genistetum parnassicae, therefore, can be considered as a vicariant of low altitude of the Astragaletum samii. From the bioclimatic point of view, the association is distributed in the meso-Mediterranean belt.
Distribution: The association is known only to Mt. Kerkis in the island of Samos (East Aegean).
Holotypus: Appendix C, Table A59, rel. 3, hoc loco. Characteristic species: Sesleria anatolica, Arenaria guicciardii, Pimpinella peregrina. Structure and ecology: The association is localized in calcareous markedly sloping rocky places with soils occurring only in the cracks and the crevices. It seems to have its optimum at 900-1000 m of altitude on a little sunshine surface especially with northern exposure, within the meso-Mediterranean bioclimatic belt. This vegetation is dominated by Sesleria anatolica which grows togheter with a rich contingent of small pulvini or creeping shrubs, such as Anthemis samia, Inula heterolepis, Noaea mucronata, Satureja spinosa var. glabra, Sideritis sipylea, etc. As concerns its dynamic role, it is a community prevalently edaphophilous, occurring within the climatophilous Pinus brutia forests, which is linked to surfaces with mature and more or less deep soils.
Structure and ecology: The alliance gathers pulvinate plant communities dominated by small tragacanthoid shrubs occurring in the mountain cacuminal stands of insular mountains. They are localized at 900-1300 m of altitude, mainly within the meso-Mediterranean bioclimatic belt. The associations falling in this sintaxon are very specialized and linked to very peculiar edaphic and bioclimatic conditions. They are circumscribed to carbonatic substrata represented by ridges and rocky outcrops, with soils present only in the cracks and crevices. The alliance is floristically differentiated by endemic species exclusive to these summit stands, that emphasized their marked geographical isolation.
Distribution: The alliance is circumscribed to the East Aegean islands of Lesvos and Chios. Notes: This syntaxon can be considered as a geographical vicariant of the Asperulion samiae.
Structure and ecology: The association is restricted to cacuminal stands at 900-967 m of altitude, on compact limestone with very superficial soils confined to the crevices of the rock. It is developed within the meso-Mediterranean bioclimatic belt on rocky surfaces usually well exposed and windy. In this vegetation small often thorny pulvini occur, among which a relevant physiognomic role is played by Astragalus angustifolius subsp. aegeicus, Inula heterolepis, Noaea mucronata, Silene urvillei, Sideritis sipylea, Anthemis aciphylla subsp. discoidea, mixed to which there are some caespitose grasses, such as Festuca pseudosupina and Koeleria lobata. It is clearly an edaphophilous vegetation closely related to very peculiar environmental conditions, such as eroded soils, marked winds and mist regime. These factors taken together do not allow a natural evolution of the vegetation towards more mature forms, such as Pinus brutia pine forest widespread in the surrounding areas.
Distribution: The association is exclusive of Mt. Olymbos in the island of Lesbos (Eastern Aegean).
Holotypus: Appendix C, Structure and ecology: This alliance brings plant communities linked to carbonatic substrates of mountain and high-mountain stands, dominated by thorny pulvini. This vegetation is distributed at altitudes above 900 m, where it is localized in places usually represented by summit rocky plateaux, ridges and cacuminal areas with very superficial and immature soils, present mainly in small depressions and crevices. From the bioclimatic viewpoint, this alliance is distributed within the meso-Mediterranean belt, with ombrotype more or less humid, even during the summer, penetrating probably in that supra-Mediterranean one. Floristically, it is differentiated by a set of endemic species with North Aegean distibution.
Distribution: The alliance is currently known only for the island of Thassos in the northen Aegean, but based on the geographic distribution of characteristic species, problably it occurs also in the coastal mountains of North Greece.
Notes: This syntaxon can be considered as a northern vicariant of the other two alliances included in the Noaeo mucronatae-Silenetalia urvillei previously described.
Holotypus: Appendix C, Structure and ecology: The association is confined to the summit very windy and sunny plateaux, consisting of crystalline limestones, located at altitudes between 900 and 1000 m, falling within the bioclimatic meso-Mediterranean belt. It occurs on rocky substrates with very superficial and immature soils, reaching its maximum expression in situations of ridge. The vegetation is dominated by thorny pulvini of Astragalus angustifolius subsp. odonianus, which forms large populations mixed with small prostrate chamaephytes (Dianthus gracilis subsp. xanthianus, Minuartia verna var. thasia, Paronychia bornmuelleri, Cerastium moesiacum subsp. glutinosum) and several hemicriptophytes represented mainly by caespitose grasses (Festuca hirtovaginata, Sesleria achtarovii, Koeleria lobata, Stipa endotricha). This vegetation is typically edaphophile, since it is linked to peculiar environmental conditions that do not allow the normal development of the soil. In edaphic more mature situations, the association is usually replaced by Juniperus excelsa woodlands.
Distribution: The association is confined to rocky outcrops of the cacuminal stands of Mt. Ipsario in the island of Thassos (northern Aegean).

Materials and Methods
The methodology used for the study regarding this kind of orophilous vegetation was based on a careful analysis of the diagnostic components that characterize the biotic and abiotic landscape of the investigated area.
As regards the bioclimatic investigations, the classification of Rivas-Martínez [64] was followed, based on the thermopluviometric data by this author. In particular, the charts built according to the criteria proposed by Walter and Leith [67] are provided, using the extrapolation data according to the method of Hijmans et al. [68,69], which are listed in the "Global climate surfaces" and relate to the period 1950-2000. These data have been taken from a map grid of 10 km 2 , in which the toponym is not given but only the geographical coordinates of the centroid of the square.
For the taxonomic treatment of the new species and subspecies described in this work, the study is based on floristic collections carried out in the investigated territories, integrated by herbarium and literature data in order to clarify their morphological relationships. As regards the taxonomic approach, the international code of botanical nomenclature [106] was followed.

Conclusions
This study allowed to improve the knowledge on the orophilous pulvinate vegetation occurring in the high-mountains of continental and insular Greece. These plant communities probably dating back to the Messinian (late Miocene) following the desiccation of the Mediterranean basin, since they are featured by steppic species, that currently have their greatest diffusion in the Irano-Turanian region. In particular, these species having usually a cushion-like habit, often thorny, seem to have penetrated in the Mediterranean after the drying up of the climate, which led to climatically challenging and very harsh environmental conditions unfit for the pre-existing flora.
It is a very peculiar and phisiognomically well characterized vegetation, very rich in endemics represented mainly by pulvinate chamaephytes and nanophanerophytes as well as often by dominance of hemicryptophytes. Most of the endemic species have a relict distribution and belong to the ancient tertiary flora, which gives a remarkable phytogeographic significance to this kind of vegetation.
Compared to the previous syntaxonomic scheme proposed by Quézel [35], nomenclaturally updated by Quézel et al. [80] and more recently taken up by Mucina et al. [84], which did not provide clear information on the classification of the plant communities present in the cacuminal stations of the Greek mountains, a new treatment is proposed in this study, based above all on the phytogeographic role of endemic species and not on the altimetric ranges, at least as regards the alliances. On the whole, this new class, namely Cerastio candidissimi-Astragaletea rumelici, replacing the previous Daphno-Festucetea which must be considered as an ambiguous name, represent a geographical vicariant in Greece and Aegean area of other syntaxa already kwown in literature [2,22,31,45,48,51]. Such cases are the following: Carici-Genistetea lobelii Klein 1972  There are numerous problems related to the conservation of these high mountain vegetation aspects. The most important are the anthropogenic pressure, due to grazing, especially goats, and the landslide of some areas which makes them particularly inconsistent, and this causes continuous erosions of various strips of vegetation. If on the one hand, thorny pulvins are not eaten by grazing animals, it is also true, however, that their presence leads continuous trampling and excessive eutrophication.
Furthermore, the ongoing climate change will certainly have a further negative influence on these peculiar high mountain plant communities and can promote a change in species strategies and growth form [107]. In fact, increasing temperatures will result in less water availability at ever higher altitudes, resulting in the impossibility for the plant communities to be able to survive using their environmental adaptations, such as spinescence, pulvinate habit, etc. All this could involve changes in the vegetation typology, with a progressive replacement of the hitherto predominant angiosperms with dwarf gymnosperms, as species of Juniperus [108,109].
For all these reasons, a strictly ecological approach could provide more detailed information on the role that these plant communities have within the entire ecosystem of the high mountains involved in this study. This research related to conservation biology could be used mainly for protection policy.
T  III III II III III V I I III II . II . 1 II . . III . II III II IV IV IV II III I III . . II . . . . . I . . III III II II IV IV III I III

Char. Ord . ERYNGIO M ULTIFIDI-ARM ERIETALIA ORPHANIDIS .
Eryng ium mult if id um  I I  I  I  V  I V  .  I V 3  I I I I I I  I  V .   I I I  I I I  I  .  I  I I  .  I I I I I  .  V  .  I I  I I I V  .  V  I V I V V  3  V I V I V I V I I I  I  I V  .  V  V  II  V  II  III  . II V I V  .  I I I V  . . I I I  .  .  I V  I I I  I  V  I I  2  I  I V I V V I V  .  I V  .  IV  .  I  .  IV  .  III V IV   S tip a end o tricha  II IV .  V  I I 2  .  .  .  I I I V  .  .  V  I I I I V V  .  I I I  .  I  .  .  .  .  I V  .  V  I  I I  I  .  I I  V  I  .  I  .  I  .  .  V  I  .  I I  . . I I  I  I I I  .  I  I I I  .  I I I

D iff . C las s CERA S TIO C AN DIDIS S IM I-A S TRA GALETEA R UM ELIC I .
A cino s alp inus subsp. merid io nalis IV  III  III  II  IV  I  IV III IV 3  IV IV II  II  I  .  V  III  II  II  3  II  II  .  V  I  IV  .  .  III V  II  II  II  .  III  II I I I I I I  I I I  I  .  V  V  I I I V  I I  .  I I I I I I III III III IV  .  III IV  II  .  .  II  III  . III .     IV III II IV I  .  I . .

Presence class
Char. Association

Presences
Presence class Presence class Presence class Presence class Presences Presences