PTERIDOPHYTE FLORA OF LESVOS (EAST AEGEAN ISLANDS, GREECE)

New data on the Pteridophyta of Lesvos (East Aegean Islands, Greece) contributing to the knowledge of their distribution and ecology are given. The presence of 24 taxa (species and subspecies) belonging to 16 genera and 7 families is confirmed whilst the occurrence of 4 more previously recorded is considered as doubtful or needs more recent confirmation. Isoetes duriei Bory, Pilularia minuta Durieu and Polystichum setiferum (Forsskal) Woynar appear to be new records for the East Aegean Islands, and Isoetes histrix Bory is new for the island of Lesvos. Furthermore the presence on Lesvos of some rare species (i.e. Notholaena marantae (L.) Desv. and Ophioglossum vulgatum L.) is confirmed. Critical comments on most of the taxa are made and dot maps of their distributions are presented. With regard to the rare species and their habitats, a need for urgent conservation measures is identified.

Geologically, Lesvos consists mainly of volcanic rocks (andesites, latite andesites, basalts, ignimbrites, peridotites, pyroxen-peridotites, olivinites etc.), although schists and marbles (in the SE part of the island), alluvial deposits (in valleys and near the coasts particularly around the bays of Kalloni and Gera), marls and limestones also occur. Peridotites, pyroxen-peridotites, olivinites are located in the SE (Peninsula of Amali) and in the central part of the island and present a variable degree of serpentinization (NIGMR, 1972(NIGMR, -1975. According to the Emberger and Sauvage climatic diagram (Emberger, 1955(Emberger, , 1959Sauvage, 1961), Lesvos belongs to the subhumid bioclimatic zone with mild winters. The climatic data come from the meteorological station of Mitilini airport (altitude: 4.8m, period: 1955-1992). The pteridophytes of Lesvos have never in the past been fully studied. Scattered records are to be found in the works of C.A. Candargy (1889), P.C. Candargy (1897Candargy ( , 1898Candargy ( , 1899, Rechinger (1943), Rauh (1949), Davis (1965), Mavromatis (1974), Yannitsaros (1977Yannitsaros ( , 1979, Edmondson (1982), Strid (1986), Axiotis (1991) and Hansen & Nielsen (1993). In this paper, which forms part of a wider study of the flora of Lesvos and its surrounding islets, new data are given as a contribution to a better knowledge of the distribution and ecology of these plants. All the records given by Davis (1965) are not original, but reproduce the older records of P.C. Candargy and Rechinger. It is to be noted that certain of the data given here, were been presented in the 5th Congress of the Hellenic Botanical Society (Bazos & Yannitsaros, 1994b).

M A T E R I A L S A N D M E T H O D S
The fioristic list which follows is based mainly on field observations and plant material collected by Artemios Yannitsaros and Ioannis Bazos during the years 1964Bazos during the years , 1974Bazos during the years , 1979Bazos during the years , 1985Bazos during the years , 1989Bazos during the years , 1990Bazos during the years , 1994Bazos during the years , 1996Bazos during the years and 1991Bazos during the years -1998 respectively. The specimens are deposited in the authors' herbaria held in Athens University (ATHU, some duplicates in B and BM). Specimens without numbers collected by Grigorios Yannitsaros (GY) in 1975, 1977 are included in the herbarium of A. Yannitsaros. Numbers within brackets, bearing the initials IB and AY refer respectively to the authors' collections, and 'obs.' refers to field observations only. We have also examined specimens collected in April 1997 by the French Pierre Authier which are kept in his private herbarium in Paris. The nomenclature of pteridophyte taxa is in accordance with Greuter et al. (1984) or Zimmer (1991). Especially for the taxa Dryopteris villarii (Bellardi) Schinz & Thell. subsp. pallida (Bory) Heywood and Polypodium cambricum L. subsp. australe (Fee) Greuter & Burdet, nomenclature follows Zimmer (in litt.). Families, genera and inferior taxa are arranged in alphabetical order. The names of species whose presence on Lesvos is confirmed are given in bold type. Transliteration of Greek localities is in accordance with Flora Hellenica (Strid & Tan, 1997) and therefore the islands Corfu, Crete and Rhodes, are mentioned in this paper as Kerkira, Kriti and Rodos respectively. General distribution data have been compiled from the works of Davis (1965), Jalas & Suominen (1972), Pichi Sermolli (1979, Greuter et al. (1984), Strid (1986) and Tutin et al. (1993).

F L O R I S T I C LIST
Equisetaceae Equisetum arvense L.
It was reported as new for both Lesvos and the East Aegean by Hansen & Nielsen (1993) from a river valley near Chidira (W Lesvos). At the same time Snogerup & Snogerup (1993) reported it as new for the flora of Samos. A previous record of E. arvense by Axiotis (1991) is considered as doubtful because of the lack of either a specimen or concrete collection data. In Greece it has scattered appearances on the mainland and seems to be rare in the Aegean Islands as it is distributed only in Kriti (Rechinger, 1943;Jalas & Suominen, 1972;Turland et al., 1993), Lesvos and Samos (Fig. 2).
General distribution. Europe, N temperate Asia and N America.
E. fluviatile L. P.C. Candargy's record of 1897 as E. limosum L. 'in humidis regionis inferioris', seems to be the only one for the East Aegean Islands and therefore requires confirmation (see also Hansen & Nielsen, 1993), although Greuter et al. (1984) accept its presence in the Eastern Aegean. Unfortunately, no voucher specimen is available as Candargy's herbarium is lost (see also Edmondson, 1982, andDiemar &Seberg, 1989). Specimens of a deviating wetland form of E. ramosissimum Desf. from the island of Samothraki were at first identified as E. fluviatile because of the very wide central cavity of the stem (Strid, in litt.). The presence of such deviating forms of E. ramosissimum on Lesvos is not unlikely. The species was reported by Lavrentiadis (1956) from Mt Voras (Kaimaktsalan) under the name E. limosum as new for Greece. Strid & Franzen (1982) report the finding of E. fluviatile on the same mountain in a marshy area known as Dobro Pole and they point out that the locality is the southernmost in the Balkan peninsula and apparently the only one in Greece. It has also been found by Voliotis (1979) in the same locality on Mt Voras. An older record by Stephanides (1948) from the island of Kerkira as E. limosum has not been recently confirmed and, therefore, may be considered very doubtful or erroneous. In the Flora Hellenica database there is also a record from the island of Kefallinia, which is almost certainly incorrect (Strid, in litt. Recorded by P.C. Candargy (1897): 'In humidis regionis inferioris'. The species is widespread in Greece and grows on wet ground mainly by streams and springs.
General distribution. Europe, SW and C Asia, NW Africa and N America.
As far as we know, these records are the first for the East Aegean Islands of this mainly west-Mediterranean species which is a very rare plant in Greece (Fig. 3). It grows in seasonally wet habitats and until now it has been reported from the islands of Evvia (Rechinger, 1961), Samothraki (Akeroyd & Preston, 1987), Agios Evstratios (Snogerup & Snogerup, 1991) and Paros (Raus, 1996). It is, however, possible that /. duriei occurs in more localities than presently known, as it is easily overlooked because of its peculiar habit.
According to Strid (in litt.) it is also distributed in the Aegean Islands of Andros, Mikonos, Milos, Tinos and Skiros (Fig. 4).
General distribution. NW Africa, W and S Europe.
According to Jermy (in litt.) these three specimens are what has been called /. heldreichii Wetts., a very rare Greek endemic species described by Wettstein (1886) from the region of Thessalia in central Greece ('submersa in pallude prope Palaeokortion planitiei Thessaliae; legit Dr. Th. de Heldreich, Julio 1885'), but they also match well specimens of /. setacea Lam. from France. Therefore, a further study of both micro-and megaspores with SEM, cytology and perhaps isoenzymes is needed for a definitive identification.
FIG. 4. Known distribution of Isoetes histrix Bory in the Aegean Islands.
This very rare species has been found in Greece for the first time by Snogerup et al. (1980) in Psathoura of N Sporades. It has also been reported recently by Snogerup & Snogerup (1991) from Agios Evstratios. Our findings are the first from the East Aegean Islands, and its Lesvos localities represent the easternmost known distribution \imits o? Vhe species (JFig,. 5y P. minuta is mduded in t\ve Red Data Book of FIG. 5. Known distribution of Pilularia minuta Durieu in Greece. Greece (Phitos et al., 1995) as Vulnerable. It is an easily overlooked species with very thin leaves l-3cm long and sporocarps usually buried in the mud (Snogerup, 1995). Most of the localities in which we have found P. minuta are in NE part of the island, E of Mandamados, near the summer settlements of Aspropotamos, Agios Stefanos and Palios. Most of the seasonal (vernal) pools in which the species was observed or collected are near the sea, at small distances from one to another, and their surface is not larger than a few square metres. The most interesting accompanying species are Callitriche brutia Petagna, Isoetes histrix, Isolepis cernua (Vahl) Roemer & Schultes, Juncus tenageia Ehrh., Lythrum borysthenicum (Schrank) Litv. and Ranunculus lateriflorus DC. The whole area mainly serves for stock-breeding (mainly sheep and cows), and increasing construction activity has been noticed during recent years. Of special interest is the area of Mikri Limni located very close to the main road connecting Mitilini with Polichnitos and to the junction of the new road to Achladeri and Kalloni. In the same locality, apart from P. minuta, other species relatively rare for Greece such as Baldellia ranunculoides (L.) Pad., Elatine alsinastrum L., Isoetes sp. (see above), Juncus tenageia, Lythrum tribracteatum Sprengel and Myriophyllum alterniflorum DC. have been found (Bazos & Yannitsaros, in press). We believe that the area of Mikri Limni should be protected not only for its scientifically interesting plant taxa but also for its biological importance with respect to all the Aegean Islands. For all the reasons mentioned above and because of the lack of any protection measures, the characterization of Pilularia minuta as Vulnerable (Snogerup, 1995) must remain in force and immediate measures must be taken to protect this extremely interesting species.

Rare and Threatened Plants of
General distribution. Endemic to the Mediterranean region known from a few scattered localities of southern Portugal, southern France, Corsica, Sardinia, Sicily, central and western coastal areas of Morocco and Algeria (Pichi Sermolli, 1979) and the three Aegean Islands mentioned above.
A. leptophylla is rather common in Lesvos (Fig. 8), although P.C. Candargy (1897) reports it as very rare ('in saxosis humidis'), without an accurate locality. Distributed mainly in the southern part of the Greek mainland, Kriti, and many of the islands.
The three cytotypes of A. ceterach (2x, 4x and 6x) treated by Viane et al. (1996) as subspecies are not distinct morphologically and can be identified by their stomata and exospore length. The diploid subsp. bivalens (D.E. Mey.) Greuter & Burdet is known from the islands of Kithira (Greuter & Rechinger, 1967) and Kefallinia (Phitos & Damboldt, 1985), the tetraploid subsp. ceterach is widespread on the Greek mainland and most of the islands, and the hexaploid subspecies (not yet described) is known from two localities, one on the island of Poros and one in eastern Peloponnisos (Viane et al, 1996). The populations of Lesvos need further study as more than one cytotype may occur on the island.
Dry walls and rock crevices, very often found in dry places exposed to the sun.
General distribution. Mediterranean area to Himalayas, scattered in C Europe.
A. obovatum Viv.  Edmondson (1982) reports it from the archipelago of Tokmakia, which is located near the NE coast of Lesvos. Our collections confirm the presence of the species on the island (Fig. 9). Regarding the rest of the East Aegean Islands, A. obovatum has been reported only from Ikaria (Rechinger, 1943;Christodoulakis, 1996), Nisiros (Papatsou, 1975) and Fourni (Rechinger, 1949). We have also seen a specimen collected by L.C. Pinatzis on the island of Chios (Delfini, 11.4.1931 so far only from Samothraki and Athos peninsula (Rechinger, 1943;Jalas & Suominen, 1972).
A. obovatum comprises two cytologically defined subspecies, the diploid A. obovatum subsp. obovatum and the autotetraploid subsp. lanceolatum (Fiori) P. Silva (in Viane et al., 1996). Details on the distribution of both subspecies are given by Jalas & Suominen (1972), Pichi Sermolli (1979) and Viane et al. (1993). Although their distribution is not yet accurately known, the diploid subspecies is distributed mainly in the Mediterranean region, Portugal and in one station in NW France, whereas the tetraploid subspecies has a western Mediterranean and eastern Atlantic distribution (W Europe, Macaronesia, N Africa). According to Demiriz et al. (1990) and Rasbach et al. (1990) Viane et al. (1996), var. protobillotii is known only from NW Turkey, S Spain and SE Greece, but the distribution of the three varieties in Europe is not yet fully known. Our specimens from above Pterounda (nos. 3282 and 3284) have leaves with acute marginal teeth and we believe that they both belong to var. protobillotii. However, study of chromosome number and micro-characters is needed for a definitive identification.
Widespread at low altitudes up to 1000m (rarely higher) in the Greek mainland and several of the islands. Crevices of dry rocks. The species grows on a variety of substrata (Zimmer, 1991) and is very common in S Greek mainland and most of the islands.

General distribution. Mediterranean region and W Europe.
General distribution. S Europe, N Africa, SW Asia to the Himalayas.
Forests, humid and shady places, rock crevices. Common throughout the Greek mainland (except in the extreme north) and many of the islands.
General distribution. Widespread in the C and E Mediterranean region, scattered in Spain.

D. filix-mas (L.) Schott
The only record for the flora of Lesvos and apparently for the flora of all East Aegean Islands is that of Axiotis (1991). Unfortunately, the lack of specimen and other collection data, obliges us to consider the occurrence of this species in Lesvos as very doubtful as it has probably been confused with D. villarii subsp. pallida. The only Aegean records of D. filix-mas are from Samothraki (in Rechinger, 1943) and Thasos (Christiansen, 1986c). Older records from Kriti are considered by Greuter (1974) as very doubtful. The species is rather widespread in damp deciduous forests of the Greek mainland. Unconfirmed records from the Ionian islands of Kefallinia, Levkas and Zakinthos (in Halacsy, 1904;Hofmann, 1968;Jalas & Suominen, 1972) are probably incorrect and belong to D. villarii subsp. pallida. P.C. Candargy (1897) reports N. marantae from Lesvos as rare, 'in saxosis', without specific locality but to our knowledge there are no other records from the island. Our finding confirms the presence of the species on Lesvos. It seems that our locality is the only one known from the East Aegean Islands. In the Greek mainland it is recorded mostly from inland localities up to 2100m (see Zimmer, 1991), whereas in the Aegean Islands it is very rare and known elsewhere only from Evvia (Rechinger, 1961;Zimmer, 1991). According to Greuter (1974) the Cretan records of the species are very doubtful. Recently, N. marantae has been reported by Viane et al. (1996) from near Methana in E Peloponnisos, which is the southernmost known limit of its distribution in Greece (see also Constantinidis, 1997) (Fig. 11). The species is calcifuge and usually grows on serpentine but not exclusively, because it also occurs on silicate rocks containing manganese (see Zimmer, 1991).
General distribution. S and C Europe, NW Africa, SW Asia, Himalayas and E tropical Africa.

Polypodium cambricum L. subsp. australe (Fee) Greuter & Burdet
Specimens examined. W of Mesotopos, Kavatsanos, humid rocks by the road to Eresos, 10 xii 1974 (AY 5753); above Pelopi, humid and shady rocks, 18 x 1991 (IB 278); near Asomatos, rock crevices in olive groves, 5 ii 1992 (IB 359); near Skalochori, humid rocks, 5 iv 1993 (IB 733); near Filia, humid and shady rocks, 5 iv 1993 (IB 742); Mt Olimbos, humid rock crevices Rauh, 1949) probably belong to this taxon. The polyploid complex of P. vulgare requires further study as the taxonomy and distribution of its three members is somewhat unsettled (Strid, in litt). P. vulgare occurs in the mountains of the Greek mainland especially above 1000m, whereas P. cambricum is widespread at low altitudes on the islands and a few coastal localities on the mainland.

General distribution. Mediterranean region and W Europe.
P. vulgare L.
Recorded from Lesvos by C.A. Candargy (1889) ('sur les rochers de la riviere Ouzia'), by P.C. Candargy (1898) as common without any other collection data, and by Rauh (1949) also without specific locality and other collection data. The presence of P. vulgare on Lesvos needs confirmation as these records probably belong to P. cambricum subsp. australe, which is rather widespread on the island (see above).
Recorded by P.C. Candargy (1898) as common 'in regione montana', but we have collected or observed P. aquilinum in lowland localities as well.
Humid and shady places in forest clearings, cleared woodland, and on stream banks. Common throughout the Greek mainland and the larger islands. Humid ground, shady and humid rocks and walls. Very common in Greece.
General distribution. Mediterranean region.

D I S C U S S I O N
During our long-term study of the flora of Lesvos (begun in 1964) it became apparent that the knowledge of its pteridophyte flora was insufficient. Most old records, and especially those of C.A. Candargy (1889), P.C. Candargy (1897Candargy ( , 1898Candargy ( , 1899 and Rauh (1949), are vague and lack full collection data. After the loss of P.C. Candargy's herbarium, the necessity for an integral study of the flora of Lesvos, complying with modern scientific concepts became imperative. Therefore, our efforts were focused to verify the presence on the island of taxa recorded by older authors and to add as much new data as possible. To this effect we have made collections in the largest possible number of areas and habitats of the island. In recent years, special consideration has been given to the investigation and collection of specimens from seasonal pools, which are located mainly in the north-eastern, central and western parts of the island, on schists and volcanic substrata. Seasonal pools are among the most fragile and threatened habitats in Greece and the Mediterranean region, and are often a habitat for rare plants, which may be greatly isolated from other populations. Plants of special interest that have been found in these habitats include the pteridophytes Isoetes duriei, I. histrix and Pilularia minuta. These are species of mainly west-Mediterranean or west-European distribution with rare and scattered appearances in Greece, and are probably undercollected because of their small size, peculiar morphology and the particularity of their habitats (Snogerup & Snogerup, 1991;Bazos & Yannitsaros, 1994a). The pteridophyte flora of Lesvos comprises 24 taxa belonging to 16 genera and 7 families. Isoetes duriei, Pilularia minuta and Polystichum setiferum are apparently new for the flora of the East Aegean Islands and /. histrix is new for Lesvos. The genus Isoetes and the family Isoetaceae are new for the flora of Lesvos, and the genera Pilularia and Polystichum as well as the family Marsileaceae are new for the flora of the East Aegean Islands as a whole. Although the occurrence of four previously recorded taxa (Cheilanthes persica, Dryopteris filix-mas, Equisetum fluviatile and Polypodium vulgare) is considered as doubtful or incorrect, the presence of three more rare species, Asplenium adiantum-nigrum, Notholaena marantae and Ophioglossum vulgatum, is confirmed.
Some of the 24 taxa of Pteridophyta of Lesvos seem to be rare or even more threatened all over Greece, because of the instability of their habitats. As already mentioned Pilularia minuta is included in the Red Data Book of Rare and Threatened Plants of Greece (Phitos et al, 1995) and the WCMC (World Conservation Monitoring Centre) lists for Greece (1997), as Vulnerable and is also protected under the Bern Convention (1979). It is to be noted that seasonal pools (Mediterranean temporary ponds) are included in the Directive 92/43/EU priority habitats. Osmunda regalis is included in the WCMC lists for Greece with '?' whilst Isoetes duriei is not included in any list of threatened plants. Furthermore neither of these two species is protected under any international convention and we recommend that both /. duriei and O. regalis be included in the WCMC lists for Greece as Vulnerable (V) and Rare (R) respectively. We also consider necessary that protection measures must be taken by the Greek State for all these three plants (i.e. /. duriei, O. regalis and P. minuta) and their sensitive habitats.
The East Aegean Islands constitute a separate phytogeographic entity with considerable particularities. They also constitute one of the thirteen floristic regions of Greece as adopted for the Flora Hellenica project (Strid & Tan, 1997). For this reason we have compiled up-to-date data regarding the pteridophyte flora of the five largest East Aegean Islands, namely Lesvos, Chios, Ikaria, Samos and Rodos (Table 1). We believe that the pteridophyte flora of four of these islands (Lesvos, Ikaria, Samos and Rodos) can be considered well-known, but for Chios, whose flora is still under study by research teams of the Lund and Patras Universities, the data are as yet insufficient. pallida and Selaginella denticulata. This number is probably an underestimation as the flora of Chios is insufficiently known. For the time being, taxa such as Anogramma leptophylla, Equisetum telmateia, E. ramosissimum and Polypodium cambricum subsp. australe, which are relatively common, have not yet been recorded from Chios.
Of the taxa listed in Table 1, Isoetes duriei, Isoetes sp., Notholaena marantae, Osmunda regalis, Pilularia minuta and Polystichum setiferum are up to now known only from Lesvos, whilst Athyrium filix-femina, Cheilanthes guanchica, Polypodium interjectum and Pteris dentata are known only from Ikaria, Asplenium bourgaei and Ophioglossum lusitanicum only from Rodos, and Cheilanthes per ska only from Samos. Furthermore, Pteris vittata is known only from Samos and Ikaria and Ophioglossum vulgatum only from Lesvos and Ikaria.
Finally, the pteridophyte flora of Lesvos seems to be the richest with 24 taxa known up to now, followed by that of Ikaria with 23 taxa.

A C K N O W L E D G E M E N T S
We express our special thanks to Dr Brigitte Zimmer (Berlin) for having determined or confirmed the determinations of a part of our collections, Mr Clive Jermy (London) for having confirmed the determinations of our Isoetes specimens as well as for his specially enlightening comments regarding this difficult genus, Prof. Arne Strid (Copenhagen) who put at our disposal data from the Flora Hellenica database, Mr Constantinos Pinatsis (Athens) who put at our disposal specimens from the private herbarium of his father Leonidas C. Pinatzis, Mr Pierre Authier (Paris) who put at our disposal specimens from his 1997 trip to Lesvos and finally Mrs Meni Ouzounelli and her husband Mr Giorgos Mastrandonakis (Mitilini) who took and accompanied us to some not easily accessible areas of Lesvos.