BACKGROUND AND AIMS: Despite extensive study of polyploidy, its origin, and ecogeographical differences between polyploids and their diploid progenitors, few studies have addressed ploidy-level structure and patterns of ecogeographical differentiation at various spatial scales using detailed sampling procedures. The pattern of coexistence of polyploids in the geophyte Allium oleraceum at the landscape and locality scale and their ecology were studied. METHODS: Flow cytometry and root-tip squashes were used to identify the ploidy level of 4347 plants from 325 populations sampled from the Czech Republic using a stratified random sampling procedure. Ecological differentiation among ploidy levels was tested by comparing sets of environmental variables recorded at each locality. KEY RESULTS: Across the entire sampling area, pentaploids (2n = 5x = 40) predominated, while hexaploids (2n = 6x = 48) and tetraploids (2n = 4x = 32) were less frequent. The distribution of tetra- and hexaploids was partially sympatric (in the eastern part) to parapatric (in the western part of the Czech Republic) whereas pentaploids were sympatric with other cytotypes. Plants of different ploidy levels were found to be ecologically differentiated and the ruderal character of cytotypes increased in the direction 4x --> 5x --> 6x with the largest realized niche differences between tetra- and hexaploids. Most populations contained only one ploidy level (77 %), 22 % had two (all possible combinations) and 1 % were composed of three ploidy levels. The majority of 4x + 5x and 5x + 6x mixed populations occurred in sympatry with uniform populations of the participating cytotypes in sites with ecologically heterogeneous or marginal environment, suggesting secondary contact between cytotypes. Some mixed 4x + 6x populations dominated by tetraploids being sympatric and intermixed with uniform 4x populations might represent primary zones of cytotype contact. Almost no mixed accessions were observed on the fine spatial scale in mixed populations. CONCLUSIONS: The results provide evidence for adaptive differences among ploidy levels, which may contribute to their complex distribution pattern. The prevalence of asexual reproduction, limited dispersal and equilibrium-disrupting processes may support local coexistence of cytotypes.

Department of Botany Faculty of Science Palacký University Slechtitelů 11 CZ 783 71 Olomouc Czech Republic

Zobrazit více v PubMed

Abrahamson WG. Demography and vegetative reproduction. In: Solbrig OT, editor. Demography and evolution in plant populations. Oxford: Blackwell; 1980. pp. 89–106.

Agapova ND. Numeri chromosomatum Magnoliophytorum florae URSS. Aceraceae – Menyantaceae. Leningrad: Nauka; 1990.

Arohonka T. Kromosomilukumäärityksiä nauvon seilin saaren putkilokasveista. Turun Yliopiston Biologian-Laitoksen Julkaisuja. 1982;3:1–12.

Åström H, Hæggström C. Generative reproduction in Allium oleraceum (Alliaceae) Annales Botanici Fennici. 2004;41:1–14.

Baack EJ. Cytotype segregation on regional and microgeographic scales in snow buttercups (Ranunculus adoneus: Ranunculaceae) American Journal of Botany. 2004;91:1783–1788. PubMed

Baack EJ. To succeed globally, disperse locally: effects of local pollen and seed dispersal on tetraploid establishment. Heredity. 2005;94:538–546. PubMed

Balfourier F, Imbert C, Charmet G. Evidence for phylogeographic structure in Lolium species related to the spread of agriculture in Europe. A cpDNA study. Theoretical and Applied Genetics. 2000;101:131–138.

Baranyi M, Greilhuber J. Genome size in Allium: quest of reproducible data. Annals of Botany. 1999;83:687–695.

Barton NH, Hewitt GM. Analysis of hybrid zones. Annual Review of Ecology and Systematics. 1985;16:113–148.

Bayer RJ, Stebbins GL. Chromosome numbers, patterns of distribution, and apomixis in Antennaria (Asteraceae: Inuleae) Systematic Botany. 1987;12:305–319.

Bierzychudek P. Patterns in plant parthenogenesis. Experientia. 1985;41:1255–1264. PubMed

ter Braak CJF, Šmilauer P. CANOCO reference manual and CanoDraw for Windows User's guide: software for canonical community ordination (version 4.5) Ithaca, NY: Microcomputer Power; 2002.

Brochmann C, Elven R. Ecological and genetic consequences of polyploidy in arctic Draba (Brassicaceae) Evolutionary Trends in Plants. 1992;6:111–124.

Brullo S, Guglielmo A, Pavone P, Scelsi F, Terrasi MC. Cytotaxonomic consideration of Allium fuscum Waldst. et Kit. (Liliaceae), a critical species of the European flora. Folia Geobotanica et Phytotaxonomica. 1996;31:465–472.

Brullo S, Guglielmo A, Pavone P, Salmeri C. Osservazioni tassonomiche e cariologiche sulle specie del ciclo di Allium paniculatum L. in Italia. Informatore Botanico Italiano. 2001;33:500–506.

Burton TL, Husband BC. Population cytotype structure in the polyploid Galax urceolata (Diapensiaceae) Heredity. 1999;82:381–390. PubMed

Capineri R, D'amato G, Marchi P. Numeri cromosomici per la Flora Italiana. 534–583. Informatore Botanico Italiano. 1978;10:421–465.

Chmielewski JG, Semple JC. The cytogeography of Aster lanceolatus. 3. Cytoecology in southern Ontario. Canadian Journal of Botany. 1983;61:1879–1886.

Davies CE, Moss D, Hill MO. EUNIS habitat classification revised 2004. Copenhagen: European Environment Agency & Paris: European Topic Centre on Nature Protection and Biodiversity; 2004.

Demek J. Hory a nížiny. Prague: Academia; 1987.

De Wilde-Duyfjets BEE. A revision of the genus Allium (Liliaceae) in Africa. Mededelingen landbouwhogeschool Wageningen. 1976 76/11.

van Dijk P, Bakx-Schotman T. Chloroplast DNA phylogeography and cytotype geography in autopolyploid Plantago media. Molecular Ecology. 1997;6:345–352.

van Dijk PK, Bijlsma R. Simulations of flowering time displacement between two cytotypes that form inviable hybrids. Heredity. 1994;72:522–535.

van Dijk P, Hartog M, van Delden W. Single cytotype areas in autopolyploid Plantago media L. Biological Journal of the Linnean Society. 1992;46:315–331.

Dobeš C, Vitek E. Documented chromosome number checklist of Austrian vascular plants. 2000. Wien: Verlag des Naturhistorischen Museums Wien.

Dobrotchaeva DN, Kotov MI, Prokudin JN. Opredetitel' vyssich rastenij Ukrainy. Kiev: Institute of Botany; 1999.

Doležel J, Binarova P, Lucretti S. Analysis of nuclear DNA content in plant cells by flow cytometry. Biologia Plantarum. 1989;31:113–120.

Dorken ME, Pannell JR. The maintenance of hybrid zones across a disturbance gradient. Heredity. 2007;99:89–101. PubMed

Duchoslav M. Comparative ecology of Allium oleraceum and A. vineale. 2000 PhD thesis, Department of Botany, Faculty of Science, Palacký University, Olomouc, Czech Republic.

Duchoslav M. Allium oleraceum and A. vineale in the Czech Republic: distribution and habitat differentiation. Preslia. 2001a;73:173–184.

Duchoslav M. Small-scale spatial pattern of two common European geophytes Allium oleraceum and A. vineale in contrasting habitats. Biologia. 2001b;56:57–62.

Duchoslav M. Effects of contrasting habitats on the phenology, seasonal growth, and dry-mass allocation pattern of two bulbous geophytes (Alliaceae) with partly different geographic ranges. Polish Journal of Ecology. 2009;57:15–32.

Ehrendorfer F. Polyploidy and distribution. In: Lewis WH, editor. Polyploidy – biological relevance. New York: Plenum; 1980. pp. 45–60.

Endler JA. Geographic variation, speciation and clines. Princeton, NJ: Princeton University Press; 1977. PubMed

Engen S, Lande R, Saether BE. The spatial role of population fluctuation and quasi-extinction risk. American Naturalist. 2002;160:439–451. PubMed

Eriksson O. Clonal life histories and the evolution of seed recruitment. In: De Kroon H, van Groenendael J, editors. The ecology and evolution of clonal plants. Leiden: Backhuys Publishers; 1997. pp. 211–226.

Felber F. Establishment of a tetraploid cytotype in a diploid population: effect of relative fitness of the cytotypes. Journal of Evolutionary Biology. 1991;4:195–207.

Felber F, Bever JD. Effect of triploid fitness on the coexistence of diploids and tetraploids. Biological Journal of the Linnean Society. 1997;60:95–106.

Fernandez Casas J, Pon-Sorolla A, Susanna A. Números cromosomáticos de plantas occidentales, 64–69. Anales del Jardin Botanico de Madrid. 1980;37:199–201.

Fialová R. Polyploidní komplexy u rodu Allium. 1996 PhD thesis, Department of Botany, Faculty of Science, Palacký University, Olomouc, Czech Republic.

Fowler N, Levin D. Ecological contrasts on the establishment of a novel polyploid in competition with its diploid progenitor. American Naturalist. 1984;124:703–711.

Fritsche F, Kaltz O. Is the Prunella (Lamiaceae) hybrid zone structured by an environmental gradient? Evidence from a reciprocal transplant experiment. American Journal of Botany. 2000;87:995–1003. PubMed

Frizen NV. Lukovyje Sibiri. Novosibirsk: Nauka; 1988.

Geitler L, Tschermak-Woess L. Cytologie der Wildbestände von Allium carinatum und Allium oleraceum bein Lunz. Naturwissenschaften. 1946;33:27.

Goldblatt P. Polyploidy in Angiosperms: monocotyledons. In: Lewis W, editor. Polyploidy, biological relevance. New York: Plenum; 1980.

Gornall RJ, Wentworth JE. Variation in the chromosome number of Parnassia palustris L. in the British Isles. New Phytologist. 1993;123:383–388.

Gotelli NJ, Ellison AM. A primer of ecological statistics. Sunderland, MA: Sinauer Associates; 2004.

Grant V. Plant speciation. 2nd edn. New York: Columbia University Press; 1981.

Guo YP, Saukel J, Mettermayr R, Ehrendorfer F. AFLP analyses demonstrate genetic divergence, hybridisation, and multiple polyploidisation in the evolution of Achillea (Asteraceae-Anthemideae) New Phytologist. 2005;166:273–289. PubMed

Hæggström CA, Åström H. Allium oleraceum (Alliaceae) in Finland: distribution, habitats and accompanying vascular plant species. Memoranda Societas pro Fauna et Flora Fennica. 2005;81:1–18.

Håkansson S. Allium vineale L. as a weed. Plant Husbandry. 1963;19:1–208.

Halkka L. Chromosome counts of Finish vascular plants. Annales Botanici Fennici. 1985;22:315–317.

Halverson K, Heard SB, Nason JD, Stireman JO. Origins, distribution, and local co-occurrence of polyploid cytotypes in Solidago altissima (Asteraceae) American Journal of Botany. 2008;95:50–58. PubMed

Hancock JF, Bringhurst RS. Evolution in California populations of diploid and octoploid Fragaria (Rosaceae): a comparison. American Journal of Botany. 1981;68:1–5.

Hardy OJ, Vekemans X. Patterns of allozyme variation in diploid and tetraploid Centaurea jacea at different spatial scales. Evolution. 2001;55:943–954. PubMed

Hardy OJ, Vanderhoeven S, de Loose M, Meerts P. Ecological, morphological and allozymic differentiation between diploid and tetraploid knapweeds (Centaurea jacea) from a contact zone in the Belgian Ardennes. New Phytologist. 2000;146:281–290. PubMed

Hintze J. NCSS 2001 – Number Cruncher Statistical System. Kaysville, UT: NCSS; 2001.

Hlaváček R. Česká republika: autoatlas. Praha: Kartografie; 2000.

Hroudová Z, Zákravský P. Ecology of two cytotypes of Butomus umbellatus. III. Distribution and habitat differentiation in the Czech and Slovak Republics. Folia Geobotanica et Phytotaxonomica. 1993;28:425–435.

Hultén E, Fries M. Atlas of north European vascular plants north of the Tropic of Cancer I. Köningstein: Koeltz; 1986.

Huntley B, Birks HJB. An atlas of past and present pollen maps for Europe. Cambridge: Cambridge University Press; 1983.

Husband BC. The role of triploid hybrids in the evolutionary dynamics of mixed-ploidy populations. Biological Journal of the Linnean Society. 2004;82:537–546.

Husband BC, Schemske DW. Cytotype distribution at a diploid–tetraploid contact zone in Chamerion (Epilobium) angustifolium (Onagraceae) American Journal of Botany. 1998;85:1688–1694. PubMed

Jauzein P, Tison JM. Hypothèses sur les liens entre Allium oleraceum L., Allium oporinanthum Brullo, Pavone & Salmeri et Allium savii Parl. Journal de Botanique de la Societé de Botanique de la France. 1999;11:55–58.

Jauzein P, Tison JM. Étude analytique du genre Allium L., sous-genre Codonoprasum (Reichenb.) Zahar., section Codonoprasum Rechenb., en France. Journal de Botanique de la Societé Botanique de la France. 2001;15:29–50.

Jay M, Reynaud J, Blaise S, Cartier D. Evolution and differentiation of Lotus corniculatus/Lotus alpinus populations from French south-western Aps. III. Conclusions. Evolutionary Trends in Plants. 1991;5:157–160.

Johnson MTJ, Husband BC, Burton TL. Habitat differentiation between diploid and tetraploid Galax urceolata (Diapensiaceae) International Journal of Plant Sciences. 2003;164:703–710.

Kao RH. Asexuality and coexistence of cytotypes. New Phytologist. 2007;175:764–772. PubMed

Kao RH. Origins and widespread distribution of co-existing polyploids in Arnica cordifolia (Asteraceae) Annals of Botany. 2008;101:145–152. PubMed PMC

Karpavičienė B. Allium oleraceum populations: ecological attachment and reproduction. Botanica Lithuanica. 2002;8:103–110.

Karpavičienė B. Allium genties rūšių paplitimas Lietuvoje. Botanica Lithuanica. 2004:19–30. Suppl. 6.

Karpavičienė B. Chromosome numbers of Allium from Lithuania. Annales Botanici Fennici. 2007;44:345–352.

Keeler KH. Distribution of polyploid variation in big bluestem (Andropogon gerardii, Poaceae) across the tallgrass prairie region. Genome. 1990;33:95–100.

Keeler KH. Population biology of intraspecific polyploidy in grasses. In: Cheplick GP, editor. Population biology of grasses. Cambridge: Cambridge University Press; 1998. pp. 183–206.

Keeler KH. Impact of intraspecific polyploidy in Andropogon gerardii (Poaceae) populations. American Midland Naturalist. 2004;152:63–74.

Kish RY. Genus Allium L. (Alliaceae) in transcarpathian flora. Subgen. Allium and Amerallium Traub. Ukrainski Botanicheskii Zhurnal. 2001;58:693–700. (in Ukrainian)

Kliber A, Eckert CG. Interaction between founder effect and selection during biological invasion in an aquatic plant. Evolution. 2005;59:1900–1913. PubMed

Koenig WD. Spatial autocorrelation of ecological phenomena. Trends in Ecology and Evolution. 1999;14:22–26. PubMed

Kolář F, Štech M, Trávníček P, Rauchová J, Urfus T, Vít P, Kubešová M, Suda J. Towards resolving the Knautia arvensis agg. (Dipsacaceae) puzzle: primary and secondary contact zones and ploidy segregation at landscape and microgeographic scales. Annals of Botany. 2009;103:963–974. PubMed PMC

Krahulcová A. Chromosome numbers in selected monocotyledons (Czech Republic, Hungary, and Slovakia) Preslia. 2003;75:97–113.

Kron P, Suda J, Husband BC. Applications of flow cytometry to evolutionary and population biology. Annual Review of Ecology, Evolution, and Systematics. 2007;38:847–876.

Laane MM, Lie T. Fremstilling av kromosompreparater med enkle metoder. Blyttia. 1985;43:7–15.

Legendre P, Anderson MJ. Distance-based redundancy analysis: testing multispecies responses in multifactorial ecological experiments. Ecological Monographs. 1999;69:1–24.

Legendre P, Legendre L. Numerical ecology. Amsterdam: Elsevier Science; 1998.

Lepš J, Šmilauer P. Multivariate analysis of ecological data using CANOCO. Cambridge: Cambridge University Press; 2003.

Levan A. Cytological studies in the Allium paniculatum group. Hereditas. 1938;23:317–370.

Levin DA. Minority cytotype exclusion in local plant populations. Taxon. 1975;24:35–43.

Levin DA. Polyploidy and novelty in flowering plants. American Naturalist. 1983;122:1–25.

Levin DA. The role of chromosomal change in plant evolution. Oxford: Oxford University Press; 2002.

Lewis WH. Polyploidy in species populations. In: Lewis WH, editor. Polyploidy – biological relevance. New York: Plenum; 1980. pp. 103–144. PubMed

Li BH, Xu XM, Ridout MS. Modelling the establishment and spread of autotetraploid plants in a spatially heterogeneous environment. Journal of Evolutionary Biology. 2004;17:562–573. PubMed

Lillie RD. Simplification of the manufacture of Schiff reagent for use in histochemical procedures. Stain Technology. 1951;25:163–165. PubMed

Lövkvist B, Hultgard UM. Chromosome numbers in south Swedish vascular plants. Opera Botanica. 1999;137:1–42.

Ložek B. Neživá příroda ve vztahu k flóře a vegetaci. In: Hejný S, Slavík B, editors. Květena České socialistické republiky 1. Praha: Academia; 1988. pp. 31–35.

Lumaret R, Guillerm JL, Delay J, Ait Lhaj Loutfi A, Izco J, Jay M. Polyploidy and habitat differentiation in Dactylis glomerata L. from Galicia (Spain) Oecologia. 1987;73:436–446. PubMed

Mable BK. Breaking down taxonomic barriers in polyploid research. Trends in Plant Sciences. 2003;8:582–590. PubMed

Mable BK. Polyploidy and self-compatibility: is there an association? New Phytologist. 2004;162:803–811. PubMed

Májovský J, Murín A. Karyotaxonomický prehlad flóry Slovenska. Bratislava: Veda; 1987.

Mandáková T, Münzbergová Z. Distribution and ecology of cytotypes of the Aster amellus aggregates in the Czech Republic. Annals of Botany. 2006;98:845–856. PubMed PMC

Masterson J. Stomatal size in fossil plants: evidence for polyploidy in the majority of angiosperms. Science. 1994;264:421–424. PubMed

McArthur ED, Sanderson SC. Cytogeography and chromosome evolution of subgenus Tridentatae of Artemisia (Asteraceae) American Journal of Botany. 1999;86:1754–1775. PubMed

Mehlich A. New extractant for soil test evaluation of phosphorus, potassium, magnesium, calcium, sodium, manganese and zinc. Communications in Soil Science and Plant Analysis. 1978;9:477–492.

Meirmans PG, Vlot EC, den Nijs JCM, Menken SBJ. Spatial ecological and genetic structure of mixed population of sexual diploid and apomictic triploid dandelions. Journal of Evolutionary Biology. 2003;16:343–352. PubMed

Měsíček J, Jarolímová V. List of chromosome numbers of the Czech vascular plants. Praha: Academia; 1992.

Meusel H, Jäger E, Weinert E. Vergleichende Chorologie der zentraleuropäischen Flora. Jena: Gustav Fischer Verlag; 1965.

Moore RJ. Index to plant chromosome numbers 1967–1971. Regnum Vegetabile. 1973;90:1–539.

Mráz P, Šingliarová B, Urfus T, Krahulec F. Cytogeography of Pilosella officinarum (Compositae): altitudinal and longitudinal differences in ploidy level distribution in the Czech Republic and Slovakia and general pattern in Europe. Annals of Botany. 2008;101:59–71. PubMed PMC

Murín A, Svobodová Z, Májovský J, Feráková V. Chromosome numbers of some species of the Slovak Flora. Thaiszia – Journal of Botany. 1999;9:31–40.

Müntzing A. The evolutionary significance of autopolyploidy. Hereditas. 1936;21:263–378.

Ohryzek J. Srovnávací biologie cytotypů česneku planého (Allium oleraceum). 2007 MSc thesis, Department of Botany, Faculty of Science, Palacký University, Olomouc, Czech Republic.

Omelchuk-Myakushko TY. Flora Evropejskoj tschasti SSSR 4. Leningrad: Nauka; 1979. Sem. 167. Alliaceae J. G. Agardh – Lukovyje; pp. 261–276.

Otto SP, Whitton J. Polyploid incidence and evolution. Annual Review of Genetics. 2000;34:401–437. PubMed

Pastor J. Karyology of Allium species from the Iberian peninsula. Phyton. 1982;22:171–200. (Horn)

Pastor J, Valdés B. Revisión del género Allium (Liliaceae) en peninsula Ibérica e Islas Baleares. Sevilla: Universidad de Sevilla Press; 1983.

Perný M, Kolarčík V, Majeský L, Mártonfi P. Cytogeography of the Phleum pratense group (Poaceae) in the Carpathians and Pannonia. Botanical Journal of the Linnean Society. 2008;157:475–485.

Petit C, Thompson JD. Species diversity and ecological range in relation to ploidy level in the flora of the Pyrenees. Evolutionary Ecology. 1999;13:45–66.

Petit C, Bretagnolle F, Felber F. Evolutionary consequences of diploid–polyploid hybrid zones in wild species. Trends in Ecology and Evolution. 1999;14:306–311. PubMed

Petřík P, Wild J. Environmental correlates of the patterns of plant distribution at the meso-scale: a case study from Northern Bohemia (Czech Republic) Preslia. 2006;78:211–234.

Pogan E, Janjun A, Malecka J, Wcislo H. Further studies in chromosome number of Polish Angiosperms. Part XIX. Acta Biologica Cracoviensia Series Botanica. 1986;28:79–81.

Pogan E, Jankun A, Sawicka Z. Further studies in chromosome numbers of Polish Angiosperms. Part 22. Acta Biologica Cracoviensia Series Botanica. 1990;31:1–17.

Quitt E. Klimatické oblasti Československa. Praha: Academia; 1971.

Ramsey J, Schemske D. Pathways, mechamisms, and rates of polyploid formation in flowering plants. Annual Review of Ecology and Systematics. 1998;29:467–501.

Rivero-Guerra AO. Cytogenetics, geographical distribution, and pollen fertility of diploid and tetraploid cytotypes of Santolina pectinata Lag. (Asteraceae: Anthemideae) Botanical Journal of the Linnean Society. 2008;156:657–667.

Rodriguez D. A model for the establishment of polyploidy in plants: viable but infertile hybrids, iteroparity, and demographic stochasticity. Journal of Theoretical Biology. 1996;180:189–196.

Ronsheim ML. Dispersal distances and predation rates of sexual and asexual propagules of Allium vineale. American Midland Naturalist. 1994;131:55–64.

Rothera S, Davy A. Polyploidy and habitat differentiation in Deschampsia cespitosa. New Phytologist. 1986;102:449–467.

Sádlo J. Diverzita vegetace České republiky, její příčiny a historický vývoj. In: Chytrý M, editor. Vegetace České republiky 1. Travinná a keříčková vegetace. Praha: Academia; 2007. pp. 53–64.

Schönswetter P, Lachmayer M, Lettner C, et al. Sympatric diploid and hexaploid cytotypes of Senecio carniolicus (Asteraceae) in the Eastern Alps are separated along an altitudinal gradient. Journal of Plant Research. 2007;120:721–725. PubMed

Segraves K, Thompson JN. Plant polyploidy and pollination: floral traits and insect visits to diploids and tetraploid Heuchera grossularifolia. Evolution. 1999;53:1114–1127. PubMed

Segraves K, Thompson JN, Soltis PS, Soltis DE. Multiple origins of polyploidy and the geographic structure of Heuchera grossularia. Molecular Ecology. 1999;8:253–262.

Seregin AP. Floristic materials and a key for the genus Allium L. (Alliaceae) species in European Russia. Bjulleten Moskovskogo Obschestva Ispytalej Prirody, Otdel Boilogicheskij. 2005;110:45–51. (in Russian)

Soltis DE, Soltis PS. Molecular data and the dynamics nature of polyploidy. Critical Reviews in Plant Sciences. 1993;12:348–352.

Soltis DE, Soltis PS. The dynamic nature of polyploid genomes. Proceedings of the National Academy of Sciences of the United States of America. 1995;92:8089–8091. PubMed PMC

Soltis DE, Soltis PS. Polyploidy: recurrent formation and genome evolution. Trends in Ecology and Evolution. 1999;14:348–352. PubMed

Soltis PS, Soltis DE. The role of genetic and genomic attributes in the success of polyploids. Proceedings of the National Academy of Sciences of the United States of America. 2000;97:7051–7057. PubMed PMC

Soltis DE, Soltis PS, Tate JA. Advances in the study of polyploidy since Plant speciation. New Phytologist. 2003;161:173–191.

Speta F. Über Oberösterreiches wildwachsende Laucharten (Allium L., Alliaceae) Linzer Biologische Beiträge. 1984;16:45–81.

Staňková H. Populační genetika polyploidního komplexu česneku planého (Allium oleraceum) na území České republiky. 2005 MSc thesis, Department of Botany, Faculty of Science, Palacký University, Olomouc, Czech Republic.

Stearn WT. Allium L. In: Tutin TG, Heywood VH, Burges NA, et al., editors. Flora Europaea 5. Cambridge: Cambridge University Press; 1980. pp. 49–69.

Stebbins GL. Variation and evolution in plants. New York: Columbia University Press; 1950.

Stebbins GL. Polyploidy, hybridization and the invasion of new habitats. Annals of the Missouri Botanical Garden. 1985;72:824–832.

Stuessy TF, Weiss-Schneeweiss H, Keil DJ. Diploid and polyploid cytotype distribution in Melampodium cinereum and M. leucanthum (Asteraceae, Heliantheae) American Journal of Botany. 2004;91:889–898. PubMed

Stutz HC, Sanderson SC. Evolutionary studies of Atriplex: chromosome races of A. confertifolia (shadscale) American Journal of Botany. 1983;70:1536–1547.

Suda J. Sympatric occurrences of various cytotypes of Vaccinium sect. Oxycoccus (Ericaceae) Nordic Journal of Botany. 2002;22:593–601.

Suda J, Malcová R, Abazid D, et al. Cytotype distribution in Empetrum (Ericaceae) at various spatial scales in the Czech Republic. Folia Geobotanica. 2004;39:161–171.

Suda J, Krahulcová A, Trávníček P, Krahulec F. Ploidy level vs. DNA ploidy level: an appeal for consistent terminology. Taxon. 2006;55:447–450.

Suda J, Weiss-Schneeweiss H, Tribsch A, Schneeweiss GM, Trávníček P, Schönswetter P. Complex distribution patterns of di-, tetra-, and hexaploid cytotypes in the European high mountain plant Senecio carniolicus (Asteraceae) American Journal of Botany. 2007a;94:1391–1401. PubMed

Suda J, Kron P, Husband BC, Trávníček P. Flow cytometry and ploidy: applications in plant systematics, ecology and evolutionary biology. In: Doležel J, Greilhuber J, Suda J, editors. Flow cytometry with plant cells. Weinheim: Wiley-Vch Verlag; 2007b. pp. 103–130.

Šopova M. Cytological study in the genus Allium from Macedonia. Godishen Zbornik na Biologickiot Fakultet Universitet Skopje, Prirodno-Matematichki. 1972;24:83–102.

Španiel S, Marhold K, Hodálová I, Lihová J. Diploid and tetraploid cytotypes of Centaurea stoebe (Asteraceae) in Central Europe: morphological differentiation and cytotype distribution patterns. Folia Geobotanica. 2008;43:131–158.

Štěpánková J. Non-adaptive hypothesis of allopatric cytotype distribution in Myosotis lamottiana (Boraginaceae) Folia Geobotanica. 2001;36:147–161.

Thompson J, Lumaret R. The evolutionary dynamics of polyploid plants: origins, establishment and persistence. Trends in Ecology and Evolution. 1992;7:302–307. PubMed

Tschermak-Woess E. Über chromosomale Plastizität bei Wildformen von Allium carinatum und anderen Allium–Arten aus den Ostalpen. Chromosoma. 1947;3:66–87.

Váchová M, Feráková V. Löve Á, editor. Taxon. 1978;27:375–392. [Report] IOPB chromosome number reports LXI.

Vakhtina LI. Chromosome numbers in some species ot the genus Allium (Alliaceae) in the Flora of USSR. Botanicheskii Zhurnal. 1984;70:700–701.

Vakhtina LI, Kudrjassova TL. Kariosistematitcheskoje issledovanie nekotorych vidov sekcii Codonoprasum roda Allium (Alliaceae) Botanicheskii Zhurnal. 1985;70:76–88.

Vosa CG. Heterochromatic banding patterns in Allium. Chromosoma. 1976;57:119–133.

Weiss H, Dobeš C, Schneeweiss GM, Greimler J. Occurrence of tetraploid and hexaploid cytotypes between and within populations in Dianthus sect. Plumaria (Caryophyllaceae) New Phytologist. 2002;156:85–94.

Wendel J. Genome evolution in polyploids. Plant Molecular Biology. 2000;42:225–249. PubMed

Wendelbo P. Alliaceae. In: Rechinger KH, editor. Flora Iranica No. 76. Graz: Akademische Druck- und Verlagsanstalt; 1971. 100.

Wetschnig W. Chromosomenzahlen Kärntner Gefäßpflanzen (Teil 3): Karyologie und Verbreitun der Allium-Arten (Alliaceae) in Kärnten. Carinthia. 1992;182:497–533.

Willmans O. On the significance of demographic processes in phytosociology. In: White J, editor. The population structure of vegetation. Dordrecht: Dr. W. Jung Publishers; 1985. pp. 15–31.

Wittmann H. Beiträge zur Karyologie de Gattung Allium und zur Verbreitung der Arten im Bundesland Salzburg (Österreich) Linzer Biologische Beiträge. 1984;16:83–104.

Xie-Kui C, Ao CQ, Zhang Q, Chen LT, Liu JQ. Diploid and tetraploid distribution of Allium przewalskianum Regel. (Liliaceae) in the Qinghai-Tibetan Plateau and adjacent regions. Caryologia. 2008;61:190–198.

Yamauchi A, Hosokawa A, Nagata H, Shimoda M. Triploid bridge and role of parthenogenesis in the evolution of autopolyploidy. The American Naturalist. 2004;164:101–112. PubMed

Zahariady C. Le sous-genre Codonoprasum (Genre Allium L., Fam. Alliaceae Agard, 1858) en Grèce et en Roumanie. IIe partie. Biologia Gallo-Hellenica. 1975;6:27–64.

Zar JH. Biostatistical analysis. 4th edn. Upper Saddle River, NJ: Prentice Hall; 1996.

Zbíral J. Analýza půd I. Jednotné pracovní postupy. Brno: Státní kontrolní a zkušební ústav zemědělský; 1995.

Zbíral J. Analýza půd III. Jednotné pracovní postupy. Brno: Ústřední kontrolní a zkušební ústav zemědělský; 1997.

New estimates and synthesis of chromosome numbers, ploidy levels and genome size variation in Allium sect. Codonoprasum: advancing our understanding of the unresolved diversification and evolution of this section

Intricate Distribution Patterns of Six Cytotypes of Allium oleraceum at a Continental Scale: Niche Expansion and Innovation Followed by Niche Contraction With Increasing Ploidy Level

Widespread co-occurrence of multiple ploidy levels in fragile ferns (Cystopteris fragilis complex; Cystopteridaceae) probably stems from similar ecology of cytotypes, their efficient dispersal and inter-ploidy hybridization

Evolutionary dynamics of mixed-ploidy populations in an annual herb: dispersal, local persistence and recurrent origins of polyploids

Ecological differentiation of diploid and polyploid cytotypes of Senecio carniolicus sensu lato (Asteraceae) is stronger in areas of sympatry

Flow cytometry, microsatellites and niche models reveal the origins and geographical structure of Alnus glutinosa populations in Europe

Drought tolerance and plasticity in the invasive knapweed Centaurea stoebe s.l. (Asteraceae): effect of populations stronger than those of cytotype and range

DNA content variation and its significance in the evolution of the genus Micrasterias (Desmidiales, Streptophyta)

Autotetraploids of Vicia cracca show a higher allelic richness in natural populations and a higher seed set after artificial selfing than diploids

High ploidy diversity and distinct patterns of cytotype distribution in a widespread species of Oxalis in the Greater Cape Floristic Region

Role of adaptive and non-adaptive mechanisms forming complex patterns of genome size variation in six cytotypes of polyploid Allium oleraceum (Amaryllidaceae) on a continental scale

Bridging global and microregional scales: ploidy distribution in Pilosella echioides (Asteraceae) in central Europe

Remarkable coexistence of multiple cytotypes of the Gymnadenia conopsea aggregate (the fragrant orchid): evidence from flow cytometry