Plant Systematics and Evolution

, Volume 243, Issue 1–2, pp 59–72 | Cite as

Ploidy level and origin of the European invasive weed Senecio inaequidens (Asteraceae)

  • L. Lafuma
  • K. Balkwill
  • E. Imbert
  • R. Verlaque
  • S. Maurice
Article

Abstract

Native to South-Africa, species of the Senecio inaequidens complex are presently invasive in Europe, Australia and South-America. Previously, different ploidy levels have been found in these different areas, with only tetraploid individuals reported in Europe, and only diploids in South-Africa and Australia. In the present study chromosome counts and flow cytometry were used to survey DNA ploidy levels in a large sample of 66 native and 21 European invasive populations. One Mexican individual was also added to the study. We found only tetraploid individuals occurring in Europe, whereas both ploidy levels, diploid and tetraploid, were found in South-Africa. Moreover, based on genome size, we suggest that two largely allopatric varieties of diploids exist in South-Africa. The Mexican individual was diploid. We suggest that European tetraploid individuals come from South-Africa and hypothesize that a hybridization event between the two DNA types of diploids occurred in the Lesotho area. The taxonomic difficulties surrounding species of theS. inaequidens complex are briefly discussed.

Key words

Senecioinaequidens Seneciomadaga-scariensis invasive species ploidy levels flow cytometry 

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Copyright information

© Springer-Verlag Wien 2003

Authors and Affiliations

  • L. Lafuma
    • 1
  • K. Balkwill
    • 2
  • E. Imbert
    • 1
  • R. Verlaque
    • 3
  • S. Maurice
    • 1
  1. 1.Institut des Sciences de l’EvolutionUniversité de Montpellier IIMontpellier cedex 05France
  2. 2.University of WitwatersrandSchool of Animal Plant & Environmental ScienceSouth Africa
  3. 3.Institut Méditerranéen d’Ecologie et de PaléoécologieUniversité de ProvenceMarseille cedex 3France

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