Phylogeny and species delimitation in Silene sect. Arenosae (Caryophyllaceae): a new section Author Eggens, Frida Department of Systematic Botany, Evolutionary Biology Centre, Uppsala University, Norbyvaegen 18 D, SE- 752 36 Uppsala, Sweden Author Jafari, Farzaneh Centre of Excellence in Phylogeny of Living Organisms, and Department of Plant Science, School of Biology, College of Science, University of Tehran, 14155 - 6455, Tehran, Iran & Department of Biological and Environmental Sciences, University of Gothenburg, 40530 Gothenburg, Sweden https://orcid.org/0000-0003-1890-7789 jafari_far1435@ut.ac.ir Author Thollesson, Mikael Department of Molecular Evolution, Evolutionary Biology Centre, Uppsala University, Norbyvaegen 18 C, SE- 752 36 Uppsala, Sweden Author Crameri, Simon Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland Author Zarre, Shahin Centre of Excellence in Phylogeny of Living Organisms, and Department of Plant Science, School of Biology, College of Science, University of Tehran, 14155 - 6455, Tehran, Iran Author Oxelman, Bengt Department of Biological and Environmental Sciences, University of Gothenburg, 40530 Gothenburg, Sweden & Gothenburg Global Biodiversity Centre, University of Gothenburg, P. O. Box 461, 40530 Goeteborg, Sweden https://orcid.org/0000-0002-6104-4264 bengt.oxelman@bioenv.gu.se text PhytoKeys 2020 159 1 34 http://dx.doi.org/10.3897/phytokeys.159.51500 journal article http://dx.doi.org/10.3897/phytokeys.159.51500 1314-2003-159-1 30136DBCF1EF530A990029ACA2A8988A 5. S. georgievskyi Lazkov, Bot. Zhurn. (Moscow & Leningrad). 84 (9): 123. 1999. Type. [Syria], Desertum Syriacum. 30 km ad austro-orient. Ab urb. Deir-Ez-Zor, vallis undulata, ass. Ephem.-car. Frequens, 15 May 1985, A. Georgievsky s.n. (Holotype: LE! [LE01051363]). Description. 20.0-50.0 cm tall, erect. Stem pubescent in lower part, scabrous, pubescent with sessile glands in upper part; with 8-12 distinct internodes, the uppermost internode obviously longer than the next upper internode. Basal leaves linear or oblanceolate, pubescent. Cauline leaves linear 10.0-40.0 x 1.0-3.0 mm, pubescent. Calyx 25.0-30.0 mm long, ovoid at anthesis and clavate in fruit, pubescent; teeth unequal; shorter ones 2.0-4.0 mm, ovate, acuminate; longer ones 4.0-6.0 mm, lanceolate, acuminate; marginal hairs long (longer than 0.5 mm), dense. Inflorescence non-divaricate, branch axile (much) less than 90°. Petal claws 10.0-12.0 mm long, glabrous; limbs 7.0-9.0 mm long, bifid, upper-surface pink, lobes oblong, petal limbs cleft to middle or more; coronal scales 2.0-2.2 mm long. Anthophore 13.0-16.0 mm long, glabrous or puberulent. Anthers exserted; filaments 12.0-15.0 mm long, glabrous. Styles exserted. First pedicel 1.0-4.0 cm in flower, 2.0-6.0 cm in fruit, erect, glabrous, apex antrorse. Capsule 12.0 mm long, oblong or ellipsoid. Seeds 0.8-1.0 mm wide. Distribution. Syria, N Iraq (Fig. 7 ). Notes. At the molecular level, we have two sequences for each ITS and rps16 and only one for RPB2 . All the three markers were sequenced for the specimen from Syria ( S. georgievskyi ID. 42), but for the specimen from Iraq, the ITS and rps16 regions were sequenced from two duplicate specimens from different herbaria. The two accessions of S. georgievskyi from Iraq and Syria do not form a monophyletic group in the species, ITS and rps16 trees (Figs 1 , 3 , 4 ). The accession from Iraq ( S. georgievskyi ID. 41) is found together with the accessions of S. chaetodonta in a moderately to strongly supported clades in the species (PP = 0.78, Fig. 1 ) and rps16 (PP = 1.00 MPB = 94% MLB = 96%, Fig. 4 ) trees, respectively. The accession from Syria is nested within a clade including S. microsperma in the species tree (Fig. 1 ) and weakly supported in rps16 tree (Fig. 4 , PP<0.75). In the ITS tree, the accessions of S. georgievskyi do not form a monophyletic group, but they are included in a strongly supported clade together with S. chaetodonta and S. striata (PP = 0.98 MPB = 86% MLB = 93%, Fig. 3 ). The morphological distinctiveness (much longer calyx, long anthophore and larger petals) speaks in favour of recognition of the species, and although chromosome numbers are unknown, we hypothesize that the incongruent pattern seen in the Syrian specimen may be explained by polyploid hybridization. Allopolyploids often grow larger than their parents ( Chen 2010 ). Silene georgievskyi is morphologically larger in floral and general habit aspects compared to both S. chaetodonta and S. microsperma . There may be a small overlap in the distributions of S. chaetodonta and S. georgievskyi , in the border area between Iraq and Syria.