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Introduction
Tripleurospermum Sch.Bip. (Asteraceae, Anthemideae) comprises ca. 40 species with a native distribution in the Northern Hemisphere: Europe, North Africa, temperate Asia and North America (Oberprieler et al., 2022). Only seven species are undoubtedly reported from Greece (Dimopoulos et al., 2024). An eighth member, Tripleurospermum disciforme (C.A.Mey.) Sch.Bip. may occur in the north-eastern part of the country (Dimitrov, 2021), but its presence in the area has not been confirmed in the last 110 years. As is the case with many Anthemideae genera, Tripleurospermum has a rather complicated taxonomic and nomenclatural history (see Inceer & Beyazoglu, 2004). The genus was successfully delimited following molecular phylogenetic analyses (Oberprieler, 2001; Inceer et al., 2018), but the distinction among its species remains problematic and species identification may be difficult, particularly in cases of incomplete herbarium specimens, i.e., when mature achenes are lacking.
The island of Lesvos is located in the eastern part of Greece and belongs to the floristic region of the East Aegean Islands (EAe; Strid & Tan, 1997). This area neighbours Anatolia (Turkey) and has been floristically enriched with several Anatolian elements (Davis, 1965). The flora of Lesvos, in particular, presents several affinities with the flora of western Turkey, as indicated by the numerous shared taxa (Bazos, 2005). Two Tripleurospermum species have been reported on Lesvos Island so far: T. rosellum (Boiss. & Orph.) Hayek (Enayet Hossain, 1975) and T. conoclinium (Boiss. & Balansa) Hayek (Bazos & Yiannitsaros, 2004). The latter is an East Mediterranean element shared between Lesvos and Anatolia (Greuter+, 2006+; Strid, 2016b, 2024; POWO, 2024). Field work in the central part of Lesvos by the second author revealed two Tripleurospermum populations that morphologically deviated from the two reported species on the island and all the remaining Greek species. After careful examination, we concluded that these populations belong to a species that has not been previously reported from Greece. This study documents the first record of the species in the country.
Material and Methods
Plant material of Tripleurospermum was recently collected on Lesvos Island. Specimens were both flowering and fruiting, as ripe achenes are important for proper identification. Dried specimens have been deposited in ATHU (the acronym follows Thiers, 2024, continuously updated). Areas with similar habitat features on Lesvos were explored, in order to locate any additional Tripleurospermum populations. The following major floristic works were used for identifying the specimens: Flora of the USSR, Volume 26 (Pobedimova, 1961), Flora of Turkey and the East Aegean Islands, Volume 5 (Enayet Hossain, 1975), and Flora Europaea, Volume 4 (Kay, 1976).
In order to investigate the chromosome number of the new Tripleurospermum populations, mature achenes were sown in pots at the facilities of the Department of Biology, National and Kapodistrian University of Athens. The seedlings were transferred in individual pots and root tips were collected. The pretreatment of the roots and the preparation of the metaphase plates follow Goula & Constantinidis (2023). The KaryoType software (Altınordu et al., 2016) and the nomenclature of Levan et al. (1964) were used for the construction of the idiogram and the classification of the chromosomes, respectively. Additional information on the chromosome numbers and karyo-type structure of Tripleurospermum was taken from recent literature (Avetisian & Oganesian, 1995; Inceer & Beyazoglu, 2004; Inceer & Hayırlıoğlu-Ayaz, 2010). The map was created in QGIS (v. 3.28.12), based on the localities reported by the authors during field work and, additionally, on localities provided by Strid (2024).
Morphology of Tripleurospermum parviflorum plants from Lesvos Island: a) a specimen cultivated at the National and Kapodistrian University of Athens, b) close-up of a capitulum with immature achenes, c) a voucher collected on Lesvos, deposited in ATHU herbarium, d) the habitat of the species at the area of Kalloni salt pan, e) achenes of the species. Scales: b) 4 mm, c) 5 cm, e) 2 mm. Photos: Katerina Goula (a, e), Charalambos Chiotelis (b, c, d).
Slika 1: Morfologija rastlin vrste Tripleurospermum parviflorum z otoka Lezbos: a) primerek, gojen na Nacionalni in Kapodistrijski univerzi v Atenah, b) košek od blizu z nezrelimi rožkami, c) vavčer, nabran na Lezbosu, shranjen v herbariju ATHU, d) življenjski prostor vrste na območju solin Kalloni, e) rožke vrste. Merila: b) 4 mm, c) 5 cm, e) 2 mm. Fotografije: Katerina Goula (a, e), Charalambos Chiotelis (b, c, d).
Description: Annual. Stems usually numerous, erect or ascending, 4–35 cm long, unbranched above. Leaves 1–3-pinnatisect, ultimate segments subulate or lanceolate-subulate. Capitula solitary, on long, pubescent to glabrescent peduncles. Involucre (4–)9–12 mm wide. Involucral bracts glabrescent, oblong to ovate-oblong, obtuse, with wide, reddish-brown to dark brown membranous margins. Receptacle conical to elongate-conical. Ligulate florets present, ligules white, 2.5–8 mm long. Disc florets yellow, eglandular at corolla lobes. Achenes oblong, slightly incurved, 1.9–2.1 mm long including the corona, dark brown to blackish at maturity, copiously mucilaginous, anteriorly with two longitudinal striations and two circular, reddish-brown resin glands, posteriorly with three thickened ribs. Achenes corona lobate, funnel-shaped, whitish, usually 0.4–0.6 mm long, ca. 1/3 to 1/4 as long as achene.
Examined specimens: GREECE. Lesvos Island, the area of Kalloni salt pan, saline soil next to the sea, 1 m a.s.l., 39°12′N/26°14′E (WGS84), 20.03.2023, Chiotelis s.n. (ATHU, det. K. Goula). Lesvos Island, ca. 900 m E of Achladeri settlement, grazed meadow, 25 m a.s.l., 39°09’N/26°17’E (WGS84), 22.03.2023, Chiotelis s.n. (ATHU, det. K. Goula).
Distribution: Tripleurospermum parviflorum is distributed in Eastern Europe and the Caucasus, extending through Turkey and the Middle East to the Arabian Peninsula and northwestern India (POWO, 2024). In Greece, the two neighbouring localities are found in the central part of Lesvos Island (Figure 2).
Figure 2:
Distribution map of the Tripleurospermum species on Lesvos (East Aegean Islands, Greece). Triangles indicate the localities of T. conoclinium, red squares T. parviflorum and circles T. rosellum.
Slika 2: Zemljevid razširjenosti vrst iz rodu Tripleurospermum na Lezbosu (Vzhodni Egejski otoki, Grčija). Trikotniki označujejo nahajališča vrste T. conoclinium, rdeči kvadrati T. parviflorum in krogi T. rosellum.
Habitat and phenology: Grazed meadows, saline soils, near the sea. Flowering from March to April, fruiting from the end of March to May.
Metaphase plate (a) and idiogram (b) of Tripleurospermum parviflorum from Lesvos Island, Greece. Red parts of the idiogram indicate satellites. Scale bars = 10 μm.
Slika 3: Metafazna plošča (a) in idiogram (b) vrste Tripleurospermum parviflorum z otoka Lezbos v Grčiji. Rdeči deli idiograma označujejo satelite. Merila = 10 μm.
3. Disc florets with eglandular corolla lobes .................. 4
– Disc florets with glandular corolla lobes ................ 5
4. Achenes with a 1–1.5 mm long corona ...T. caucasicum
– Achenes with a corona shorter than 1 mm, usually 0.4–0.6 mm long .....................................T. oreades
5. Achenes non-mucilaginous; corona absent or, if present, shorter than 0.3 mm ........................................ 6
– Achenes at least slightly mucilaginous; corona absent or, if present, longer than 0.3 mm ............. 7
6. Involucral bracts with pale margins; achenes black at maturity with a corona 0.1–0.3 mm long .............................................................................. T. tempskyanum
– Achenes usually pale brown at maturity, corona lacking or, if present, up to 0.3 mm, but then involucral bracts dark-margined ........ T. tenuifolium
7. Achenes without a corona ......................................... 8
– Corona of the achenes at least 0.3 mm long ........................................................................... T. rosellum
8. Ligulate florets absent; involucral bracts with pale margins; achenes only slightly mucilaginous ............................................................................... T. disciforme
– Ligulate florets present; involucral bracts with brown margins; achenes copiously mucilaginous .... ......................................................... T. conoclinium
Discussion
The newly discovered Tripleurospermum populations on the island of Lesvos belong to T. parviflorum (Willd.) Pobed., a species that has never been previously recorded in Greece.
A quick diagnostic character that distinguish this species from Tripleurospermum conoclinium and T. rosellum, the two species also found on Lesvos, is its annual lifespan (reported by Pobedimova, 1961; Enayet Hossain, 1975; Kay, 1976). As additional features, T. conoclinium has achenes without a corona (see Enaet Hossain, 1975; Kay, 1976; Strid, 2016a), whereas T. parviflorum has achenes with a corona measuring 0.4 – 0.6 mm long (Pobedimova, 1961; Enayet Hossain, 1975; our counts). According to specimens examined from Lesvos, T. rosellum has brown achenes with an even longer corona, usually 0.6 – 0.9 mm, whereas T. parviflorum has achenes that become dark brown to blackish at maturity (Enayet Hossain, 1975). Among the rest of the species that occur in Greece, only T. inodorum (L.) Sch. Bip. is annual, but it has disc florets glandular at the corolla lobes and non-mucilaginous achenes with a very short, marginiform corona (Pobedimova, 1961; Enayet Hossain, 1975; Kay, 1976; our observations). T. parviflorum, on the other hand, lacks glandular corolla lobes at the disc florets and its achenes are copiously mucilaginous (Enayet Hossain, 1975; our observations).
The chromosome number of 2n = 2x = 18 has been reported for Tripleurospermum parviflorum in material from Armenia (Avetisian & Oganesian, 1995), north-east Turkey (Inceer & Beyazoglu, 2004) and west Turkey (Inceer & Hayırlıoğlu-Ayaz, 2010). The karyological study of the Armenian population also revealed the presence of a B chromosome in some metaphases (2n = 2x = 18 + 1B, Avetisian & Oganesian, 1995). Our count from the Greek population is in accordance with the previous records and also showed a diploid complement (2n = 2x = 18). This is the fourth chromosome count for Tripleurospermum parviflorum. The examination of the karyotype formula of the Greek population (plants from the Kalloni area were investigated) revealed that most chromosomes are meta-centric (m), while there is an equal number of submetacentric (sm) and subtelocentric (st) chromosomes in the complement, as follows: 2n = 2x = 10m + 4sm + 4st4sat. All st chromosomes bear small satellites on their short arm. The karyotype formula of the Greek population slightly differs from that published by Inceer & Beyazoglu (2004) in the number of sm and st chromosomes and the lack of sat-DNA on the st chromosomes (2n = 2x = 10m + 6sm + 2st).
Tripleurospermum parviflorum reported herein from Lesvos Island is a new record for the Greek flora. Its discovery further supports an assemblage of plant species shared between Lesvos and Anatolia (Turkey), among which Anthemis aciphylla Boiss., Centaurea reuteriana Boiss., and Tripleurospermum conoclinium are good examples from the Asteraceae family. They all indicate phytogeographical bounds between the two areas as the result of spatial proximity and palaeogeographical connections (Drinia et al., 2002; Bazos, 2005). Therefore, the presence of T. parviflorum on Lesvos should not be considered as a surprise. The species has been recorded in the Turkish provinces of Çanakkale and İzmir (Enayet Hossain, 1975; GBIF, 2024), which surround the island of Lesvos. The closest Turkish locality to the Greek T. parviflorum populations lies at approximately 70 km linear distance to the north-northwest, on the Turkish island of Bozcaada (Tenedos; Rechinger, 1943). The populations on Lesvos and Bozcaada seem to form the westernmost known distribution for the species.
Orcid profile
