Bocconea 28: 425-463 https://doi.org/10.7320/Bocc28.425 Version of Record published online on 22 November 2019 Cristina Cattaneo & Mauro Grano Checklist updating and analysis of the flora of Symi island and of the nearby island of Seskli (Dodecanese, Greece) Abstract Cattaneo, C. & Grano, M.: Checklist updating and analysis of the flora of Symi island and of the nearby island of Seskli (Dodecanese, Greece). –– Bocc. 28: 425-463. 2019. –– ISSN: 1120- 4060 printed, 2280-3882 online. A contribution to the knowledge of the vascular flora of Symi and the nearby island of Seskli is pre- sented, being an update of the vascular flora of Symi and Seskli islands, 32 years after the first check- list published by Carlström. The occurrence of Limonium hirsuticalyx is reported on Symi for the first time; for Seskli, 41 new floristic records are provided, in addition to a species inquirenda: Limonium cfr. hirsuticalyx / meyeri. The strong floristic affinity between Symi and SW Anatolia, to which Symi was linked until the upper Pleistocene, is confirmed by the large number of range- restricted and rare taxa occurring on Symi and for the most part shared with the Muğla province in SW Anatolia. Despite its relatively recent insular isolation, Symi hosts a fair rate of endemics, including three single-island endemics: Allium symiacum, A. panormitisi and Origanum symes. Key words: floristic investigation, endemism, active speciation, ruderal species. Introduction Symi island belongs to the Dodecanese. It is located between Rhodes and the Turkish coast (Datça Peninsula, Muğla Province) from which it is only 5 km (Fig. 1). Symi has a surface area of 58 km² and a coastline of 85 km, with numerous bays, capes and steep cliffs. Symi is surrounded by smaller, uninhabited rocky islands, the largest of which are Nimos (N) and Seskli (S). Symi is chiefly hilly and culminates in Mt. Vigla at 620 m a.s.l. The island together with the peninsulas Daraçya and Reşadiye is made up mainly of Mesozoic limestone (Carlström 1987), which makes up the high costal cliffs and the deep inlet of Dhysalonas, Nanou, Lapathos and Ladhi. There are also some areas of flysch (Desio 1924a, 1924b). Due to the island’s rocky nature, cultivated land is very scarce, except in the Pedi and Niborios valleys. Symi lacks surface water courses; there are only wells and cisterns. The climate is semi-arid Mediterranean with short, mild, wet winters followed by long, hot dry summers (Galanos & Tzanoudakis 2017). The island’s eastern part and the surrounding uninhabited islands are included in the Natura 2000 network of protected areas (GR4210025), as they host to rare bird species as well as old conifer wood- 426 Cattaneo & Grano: Checklist updating and analysis of the flora of Symi island ... Fig. 1. Geographical position of Symi and Seskli Islands in the Aegean Sea. land of Cupressus sempervirens L. with stands of Pinus brutia Ten., covering the island’s SE part (www.ypeka.gr). The island of Seskli was completely uninhabited until the 1980s. It is property of the Panormitis Monastery and lies about 1 km south of the island of Symi (Broggi 2002). Its surface area is 1,826 Km² with a maximum altitude of 117 m. The island is fairly flat with several cultivated and terraced areas with olive groves. Most of the island is characterized by low evergreen sclerophyllous maquis organized around arborescent junipers. It is a pri- mary maquis whose most representative elements are Pistacia lentiscus L. (pulvinate) and Juniperus turbinata Guss. Th. Orphanides was the first to collect plants on Symi, in 1856, and his data have been reported in Heldreich (1877), Pampanini (1926), Rechinger (1944), Ciferri (1944), and Davis (1965-1985). Subsequently Desio during his travels in the SE Aegean area, gathered several specimens on Symi, which were reported by Pampanini (1926), Rechinger (1944), Ciferri (1944), and Davis (1965-1985). Rechinger visited Symi on 28-29 June 1935, includ- ing its highest peak Mt. Vigla, and later published his records (Rechinger 1944). The mate- rial collected in 1961 by Gathorne-Hardy was reported by Davis (1965-1985). Davis him- self carried out botanical research on Symi in 1981 (Davis 1965-1985). Finally, the most substantial contribution to the knowledge of the island’s flora was provided by Carlström (1987). She visited Symi in different times between July 1981 and October 1982. Keitel & Remm (1991) studied the orchid flora of the island. In 2001, Jahn collected several taxa on Symi: his records have been published by Strid (2016). Later Chilton (2010) compiled a plant list of Symi. The most recent contributions to the flora of Symi have been provided by Galanos (2016), Galanos & Tzanoudakis (2017; 2019), Burton & Tan (2017), and Cattaneo Bocconea 28 — 2019 427 & Grano (2017; 2018a). The floristic data relating to Symi have been excerpted from all these published sources and from Strid (2016). Carlström investigated Seskli on 11.06.1982 and recorded 70 species. Formerly, on 31.05.1966 Bothmer visited the island, where he col- lected 7 species, and the small island of Trambeto (W of Seskli). The first inventory of the vascular flora of Seskli was drawn up by Carlström (1987). An unpublished checklist of the plants collected on Seskli by Carlström and Bothmer has been kindly provided by Strid. The present authors add here their own data on the flora of Seskli. Materials and methods Symi has been investigated by the authors on three occasions: from 30 July to 11 August 2017, from 26 to 30 April 2018 and on 26 and 27 April 2019. On 7 August 2017 and 29 April 2018, two excursions were made to the island of Seskli, south of Symi. All speci- mens are kept in the first author’s personal herbarium. Plant identifications are mainly based on Rechinger (1944, 1949), Rechinger & Rechinger, (1951), Davis (1965-1985), Davis & al. (1988), Tutin & al. (1964-1980, 1993), Greuter & al. (1984-1989), Pignatti (1982), Strid & Tan (1997, 2002), Brullo & Erben (2016), and Strid (2016). Species nomenclature mostly follow Greuter & al. (1984-1989), Greuter & Raab-Straube (2008) and Euro+Med (2006-). Regarding the distribution of the genus Limonium, Brullo & Erben’s (2016) innovative treatment has been followed. The definition and naming of fam- ilies comply with Strid (2016), and information regarding the presence of species on Symi has been extractated from the database “Flora of Greece Web” (Dimopoulos & al. 2018). The status of endemic taxa recorded for Symi is based on Dimopoulos & al. (2018). With regard to the status of alien taxa, Arianoutsou & al. (2010) and Dimopoulos & al. (2018) have been followed. The life-form and chorological categories follow Dimopoulos & al. (2018). For recording altitudes and geographical coordinates, the Android application AlpineQuest GPS was used. Place names mentioned in the text follow the map of Symi produced by Terrain Cartography Group in 2009. The authors established an updated checklist of the flora of Symi and Seskli, in which all taxa recorded from either island from 1987 to date is included. The database of Lund (LD) Herbarium (https:// www.biomus.lu.se/en/botanical-collections) was consulted for compiling the checklists and for the correct identification of several specimens (last access 01/10/2019). Unless oth- erwise specified, the term “endemic” is used to denote taxa with a distribution area con- fined to Greece plus SW Turkey and the term “range-restricted” refers to taxa with a lim- ited area of distribution not exceeding a distance of 500 km (sensu Dimopoulos & al. 2018). SW Turkey refers to the area between the provinces of Aydin, Muğla, Denizli, Burdur, Isparta and Adalia. Results Features of Symi’s flora This paper brings an updated inventory of the vascular flora of Symi and Seskli, 32 years after Carlström’s (1987) checklist. It also highlights Symi’s endemism rate, which is substantial when one considers Symi’s recent origin as an island (Sfenthourakis & Triantis 428 Cattaneo & Grano: Checklist updating and analysis of the flora of Symi island ... 2017). Symi has a varied landscape. The northern part of the island is covered with low xeric scrub vegetation (phrygana) that results from protracted and reiterated anthropic impact (land cultivation and overgrazing). The most representative species of this plant community are Thymbra capitata (L.) Cav., Origanum onites L., Sarcopoterium spinosum (L.) Spach, and Salvia fruticosa Mill. The southern part of the island hosts pre-anthropic conifer woodland of great scientific value, dominated by Cupressus sempervirens f. hori- zontalis (Mill.) Loudon with stands of Pinus brutia. Two woodland communities have been recognised: species-poor Quercus coccifera-Cupressus sempervirens woods, and Pistacia lentiscus-Cupressus sempervirens woodland, which pertains mainly to the ther- mo-Mediterranean vegetation belt (Brofas & al. 2006). In addition, Symi, in the crevices of hard limestone cliffs, hosts a very interesting chasmophytic flora, characterized by many rare and endemic species (Phitos & al. 2009) such as Hirtellina fruticosa (L.) Dittrich, Lomelosia variifolia (Boiss.) Greuter & Burdet, Teucrium montbretii subsp. heliotropiifoli- um (Barbey) P. H. Davis, and Linum arboreum L. It occurs along the SE coast (Dhysalonas, Nanou, Faneromeni) and the SW coast (Lapathos and Ladhi). Analysis of the flora To date, the vascular flora of Symi, including cultivated and naturalized taxa, comprises 679 taxa (678 species and one additional subspecies), belonging to 364 genera and 93 fam- ilies. Alien taxa not well established in Greece, such as Schinus molle L., Senecio angula- tus L., and Euphorbia hypericifolia L., are disregarded. The most species-rich families are Asteraceae (90 taxa), Fabaceae (72 taxa), and Poaceae (67 taxa). Apiaceae (31 taxa) and Lamiaceae (30 taxa) are also well represented. As for life-forms, therophytes predominate, followed by hemicryptophytes, geophytes, chamaephytes, phanerophytes, and halophytes (Table. 1).