Abstract
Heliosperma includes about 20 taxa which are divided into alpestre, macranthum and pusillum clades based on nuclear and plastid data. Based on microstructural qualitative and quantitative seed characters of H. macranthum, H. alpestre and of nine Balkan species, we found that the species assigned to the pusillum clade are highly variable and differ from H. alpestre and H. pusillum subsp. pusillum. Two low elevation species (H. retzdorffianum and H. nikolicii) were clearly separated from the H. pusillum group, which includes alpine taxa. Newly described characters of the seeds, e.g. two hilum chambers, two rows in crest and black colour could be treated as characteristic for lowland endemics. Microstructural differences in seed character of Heliosperma species seems to be mainly driven by ecological factors resulting from the elevation gradients. Pollen is undifferentiated between species, its viability (stainability) is high, chromosome number is 2n = 26, which differs from the number reported so far (2n = 24).
References
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<p>Bertel, C., Rešetnik, I., Frajman, B., Erschbamer, B., Hülber, K. & Schönswetter, P. (2018) Natural selection drives parallel divergence in the mountain plant <em>Heliosperma pusillum</em> s.l. <em>Oikos </em>127: 1355–1367. https://doi.org/10.1111/oik.05364</p>
<p>Boissier, E. (1854) <em>Diagnoses Plantarum Orientalium Novarum</em>, Serie 2 (1). Lipsiae Apud B. Herman, Leipzig, 149 pp.</p>
<p>Chater, A.O., Walters, S.M. & Akeroyd, J.R. (1993) <em>Silene</em>. <em>In</em>: Tutin, T.G., Burges, N.A., Chater, A.O., Edmondson, J.R., Heywood, V.H., Moore, D.M., Valentine, D.H., Walters, S.M. & Webb, D.A. (Eds.) <em>Flora Europaea 2<sup>nd</sup> Ed.</em>, vol. 1. Cambridge University Press, Cambridge, pp. 191–218.</p>
<p>Cobon, A.M. & Murray, B.G. (1983) Unstable B chromosomes in<em> Silene maritima </em>With. (Caryophyllaceae). <em>Botanical Journal of the Linnean Society</em> 87: 273–283. https://doi.org/10.1111/j.1095-8339.1983.tb00995.x</p>
<p>Degen, A. (1937) <em>Flora velebitica</em>, Vol. 2. Verlag der Ungar. Akademie der Wissenschaften, Budapest, 660 pp.</p>
<p>EC (European Commission) (2013) Interpretation Manual of European Union Habitats. <em>EUR </em>28: 1–144.</p>
<p>Frajman, B. & Rabeler, R.K. (2006) Proposal to conserve the name <em>Heliosperma</em> against <em>Ixoca </em>(<em>Caryophyllaceae</em>, <em>Sileneae</em>). <em>Taxon </em>55 (3): 806–807. https://doi.org/10.2307/25065663</p>
<p>Frajman, B. & Oxelman, B. (2007) Reticulate phylogenetics and phytogeographical structure of <em>Heliosperma</em> (<em>Sileneae</em>, Caryophyllaceae) inferred from chloroplast and nuclear DNA sequences. <em>Molecular Phylogenetics and Evolution</em> 43 (1): 140–155. https://doi.org/10.1016/j.ympev.2006.11.003</p>
<p>Frajman, B., Eggens, F. & Oxelman, B. (2009) Hybrid origins and homoploid reticulate evolution within <em>Heliosperma</em> (<em>Sileneae</em>, Caryophyllaceae)—a multigene phylogenetic approach with relative dating. <em>Systematic Biology </em>58 (3): 328–345. https://doi.org/10.1093/sysbio/syp030</p>
<p>Greuter, W. (1997) Silene Sect. <em>Heliosperma</em> (Reinchenb.) Ledeb. <em>In</em>: Strid, A. & Tan, K. (Eds.) <em>Flora Hellenica</em>, Vol. 1. Koeltz Scientific Books, Federal Republic of Germany, pp. 293–295.</p>
<p>Grisebach, A. (1843) <em>Spicilegium florae rumelicae et bithynicae exhibens synopsin plantarum</em>, Vol. 1. Prostat apud Fridericum Vieweg et filium, Brunsvigae, 414 pp.</p>
<p>Guangchuang, Y. (2020) Using ggtree to visualize data on tree-like structures. <em>Current Protocols in Bioinformatics </em>69: e96. https://doi.org/10.1002/cpbi.96</p>
<p>Halbritter, H. & Svojtka, N. (2016) <em>Heliosperma alpestre</em>. <em>In</em>: PalDat - A palynological database. Available from: https://www.paldat.org/pub/Heliosperma_alpestre/301630 (accessed 10 March 2022).</p>
<p>Hoseini, E., Ghahremaninejad, F., Assadi, M. & Nejati Edalatiyan, M. (2017) Seed micromorphology and its implication in subgeneric classification of <em>Silene</em> (Caryophyllaceae, Sileneae). <em>Flora </em>228: 31–38. https://doi.org/10.1016/j.flora.2017.01.006</p>
<p>Husson, F., Josse, J. & Pagès, J. (2010) Principal component methods-hierarchical clustering – partitional clustering: why would we need to choose for visualizing data? <em>Technical Report</em>. [17 pp.]</p>
<p>Jacquin, J.N. (1773) <em>Florae Austriacae, sive, Plantarum selectarum in Austriae archiducatu: sponte crescentium icones, ad vivum coloratae, et descriptionibus, ac synonymis illustratae</em>, Vol. 1. typis Leopoldi Joannis Kaliwoda, aulae imperialis typographi, Viena, 61 pp. + 100 tabs. https://doi.org/10.5962/bhl.title.457</p>
<p>Kassambara, A. & Mundt, F. (2020) <em>Factoextra: extract and visualize the results of multivariate data analyses. R package version 1.0.7</em>.</p>
<p>Lê, S., Josse, J. & Husson, F. (2008) FactoMineR: an R package for multivariate analysis. <em>Journal of Statistical Software</em> 25: 1–18. https://doi.org/10.18637/jss.v025.i01</p>
<p>Linneaus, C. (1973) <em>Species plantarum</em>, Vol. 1. Salvius, Stockholm, 560 pp.</p>
<p>Malý, K. (1903) <em>Heliosperma</em> (Silene) Retzdorffianum. <em>Österreichische Botanische Zeitschrift</em> 53: 357–359. https://doi.org/10.1007/BF01794437</p>
<p>Malý, K. (1907) Bemerkungen Uber die Arten der Gattung <em>Heliosperma </em>aus der Verwandtschaft des H. Retzdorffianum. <em>In:</em> Hoernes, M. (Eds.) <em>Wissenschaftliche Mitteilungen aus Bosnien und der Herzegovina</em>, Vol. 10. Adolf Holzhausen, Vienna, pp. 629<strong>–</strong>634.</p>
<p>Markgraf, F. (1931) Pflanzen aus Albanien 1928. <em>Denkschriften der Kaiserlichen Akademie der Wissenschaften Klasse</em> 102 (8): 317–360.</p>
<p>Melzheimer, V. & Polatschek, A. (1992) Revision des <em>Silene</em> (<em>Heliosperma</em>) <em>pusilla</em> agg. (<em>Caryophyllaceae</em>) für die Flora Österreichs. <em>Phyton (Horn, Austria)</em> 31: 281–306.</p>
<p>Mouchet, M., Guilhaumon, F., Villéger, S., Mason, N.W.H., Tomasini, J.-A. & Mouillot, D. (2008) Towards a consensus for calculating dendrogram-based functional diversity indices. <em>Oikos</em> 117 (5): 794–800. https://doi.org/10.1111/j.0030-1299.2008.16594.x</p>
<p>Neumayer, H. (1923) Einige Fragen der speziellen Systematik, erläutert an einer Gruppe der Gattung <em>Silene</em>. <em>Oesterreichische Botanische Zeitschrift </em>72: 276–287. https://doi.org/10.1007/bf01660057</p>
<p>Niketić, M. & Stevanović, V. (2007) A new species of <em>Heliosperma</em> (Caryophyllaceae) from Serbia and Montenegro. <em>Botanical Journal of the Linnean Society</em> 154: 55–63. https://doi.org/10.1111/j.1095-8339.2007.00643.x</p>
<p>Niketić, M., Stevanović, V. & Tomović, G. (2007) Nomenclatural and taxonomic notes on the flora of Serbia and Balkan Peninsula. I. Caryophyllaceae. <em>Archive of Biological Science </em>59 (4): 387–396. https://doi.org/10.2298/ABS0704387N</p>
<p>Pagès, J. (2004) Analyse Factorielle de Donnees Mixtes. <em>Revue Statistique Appliquee</em> 4: 93–111.</p>
<p>Pančić, J. (1875) <em>Elenchus plantarum vascularum quas aestate a. 1873. in Crna Gora. Legit Dr. J. Pančić</em>. In typgraphia status, Belgradi, 106 pp. https://doi.org/10.5962/bhl.title.9849</p>
<p>Petchey, O.L. & Gaston, K.J. (2002) Functional diversity (FD), species richness and community composition. <em>Ecology Letters</em> 5 (3): 402–411. https://doi.org/10.1046/j.1461-0248.2002.00339.x</p>
<p>POWO (2022) <em>Plants of the World Online</em>. Available from: http://www.plantsoftheworldonline.org/ (Accessed 30 May 2022).</p>
<p>R Core Team (2021) <em>R: A language and environment for statistical computing</em>. R Foundation for Statistical Computing, Vienna, Austria. Available from: https://www.R-project.org/ (Accessed 10 March 2022).</p>
<p>Rafinesque, C.S. (1840) <em>Autokon Botanikon</em>, <em>Or, Botanical Illustrations of 2500 New, Rare Or Beautiful Trees, Shrubs, Plants, Vines, Lilies, Grasses, Ferns &c, of All Regions, But Chiefly North America, with Descriptions &c and 2500 Self Figures Or Specimens</em>. Arnold Arboretum, Philadelphia, 200 pp.</p>
<p>Reichenbach, H.G.L. (1841) <em>Der Deutsche Botaniker Erster Band. Das Herbarienbuch: Erklärung des natürlichen Pflanzensystems, systematische Aufzählung, Synonymik und Register der bis jetzt bekannten Pflanzengattungen</em>. Der Arnolbitchen Buchhanblung, Dresden, Leipzig, 240 pp.</p>
<p>Reichenbach, H.G.L. (1844) <em>Icones florae Germanicae et Helveticae, simul Pedemontanae, Tirolensis, Istriacae, Dalmaticae, Austriacae, Hungaricae, Transylvanicae, Moravicae, Borussicae, Holsaticae, Belgicae, Hollandicae, ergo Mediae Europae</em>. Friedrich Hofmeister, Leipzig, 84 pp.</p>
<p>Schliep, K., Potts, A.J., Morrison, D.A. & Grimm, G.W. (2017) Intertwining phylogenetic trees and networks. <em>Methods in Ecology and Evolution</em> 8: 1212–1220. https://doi.org/10.7287/peerj.preprints.2054</p>
<p>Sheidai, M., Nikoo, M. & Gholoipour, A. (2008) Cytogenetic variability and new chromosome number reports in <em>Silene</em> L. species (Sect. Lasiostemones, Caryophyllaceae). <em>Acta Biologica Szegediensis</em> 52 (2): 313–319.</p>
<p>Shuka, D., Tan, K., Hallaçi, B. & Shuka, L. (2020) Additions to the flora of North Albania. <em>Phytologia Balcanica</em> 26 (3): 517–522. https://doi.org/10.3372/wi.38.38206</p>
<p>Singh, R.J. (2003) <em>Plant Cytogenetics</em>, 2<sup>nd</sup> ed. CRC Press, Boca Raton, 512 pp.</p>
<p>Thiers, B. (2022 [continuously updated]) Index herbariorum: a global directory of public herbaria and associated staff. New York Botanical Garden’s virtual herbarium, New York. Available from: http://sweetgum.nybg.org/science/ih/ (Accessed 10 March 2022).</p>
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