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 Silene section Arenosae Eggens, F.Jafari & Oxelman, sect. nov. Type. Silene arenosa K. Koch. Description. Annuals. Stems erect or ascending, 5-70 cm, often pubescent at least below, internodes often with sessile glands on upper part. Basal leaves lanceolate to oblanceolate, +/- covered with unicellular trichomes; cauline leaves linear, lanceolate or oblanceolate, pubescent. Inflorescence an apical, uneven dichasium with long internodes, several later axillary inflorescences from upper stem nodes usually present. Flowers usually nocturnal (e.g. S. austroiranica , S. linearis ), rarely diurnal ( S. exsudans Boiss. & Heldr., S. leyseroides , S. microsperma subsp. cypria Eggens, F.Jafari & Oxelman, nom nov.). Calyx teeth often with distinct mucro, heteromorphic with three longer, often acute, narrowly lanceolate teeth with a narrow transparent margin, the other two teeth shorter, slightly broader, rounded and with a broad transparent margin; margin usually densely ciliate. Primary calyx veins mostly green (or reddish when exposed), often raised; secondary veins obscure; area between veins whitish. Styles 3. Petal limb upper surfaces white or pink. Capsule ellipsoid, oblong or obovate. Seeds reniform, hilum sunken, side flat, with a dorsal groove, testa smooth or papillate. Distribution and habitat. SW Asian, from South Mediterranean Turkey to Armenia southward to Egypt and the Arabian Peninsula and eastward to Pakistan (Fig. 7 ). Most taxa have rather limited distributions, except S. chaetodonta and S. leyseroides that are found from South-Central Turkey to Afghanistan and from Iraq to Pakistan, respectively. All species grow in dry sandy or gravelly habitats. Figure 7. Distribution map of S. sect. Arenosae . Each color code corresponds to one taxon: A S. arenosa B S. austroiranica C S. chaetodonta D S. exsudans E S. georgievskyi F S. leyseroides G S. linearis H S. microsperma subsp. cypria I S. microsperma subsp. maritima J S. microsperma subsp. microsperma K S. microsperma subsp. modesta L S. striata . Notes. Melzheimer (1988) considers S. rhadinocalyx Stapf [in Akad. Wiss. Wien, Math.-Naturwiss. Kl., Denkschr. 51: 352 (1886)] to belong to this group, but examination of the type led us to conclude that this taxon is closer to either of the SW Anatolian species S. cariensis Boiss. or S. vittata Stapf.