The origin of a novel form of Senecio (Asteraceae) restricted to sand dunes in southern Sicily

Authors

  • Mark A. Chapman,

    Corresponding author
    1. Department of Biological Sciences, Vanderbilt University, VU Station B 351634, Nashville, TN 37235-1634 USA;
    2. Sir Harold Mitchell Building, School of Biology, University of St Andrews, St Andrews, Fife KY16 9TH, UK
      Author for correspondence: Mark A. Chapman Tel: +1 615 9363893 Fax:+1 615 3436707 Email: mark.a.chapman@vanderbilt.edu
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  • Richard J. Abbott

    1. Sir Harold Mitchell Building, School of Biology, University of St Andrews, St Andrews, Fife KY16 9TH, UK
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Author for correspondence: Mark A. Chapman Tel: +1 615 9363893 Fax:+1 615 3436707 Email: mark.a.chapman@vanderbilt.edu

Summary

  • • The taxonomy of diploid Mediterranean Senecio sect. Senecio (Asteraceae) is complex, owing to a recent species radiation, high morphological plasticity and occasional interspecific hybridization.
  • • A study was conducted to resolve the origin of a novel form of Senecio restricted to sand dunes in southern Sicily, Italy. This has been described previously as morphologically intermediate to Senecio gallicus and Senecio glaucus ssp. coronopifolius, indicating a possible hybrid origin, or as a variant of Senecio leucanthemifolius.
  • • Plants of this form grown in a glasshouse were morphologically intermediate to S. glaucus and S. leucanthemifolius, but were also similar to some cultivated individuals of S. gallicus. No evidence for a hybrid origin was obtained from a survey of random amplified polymorphic DNA variation; instead the plants surveyed were most closely allied to Tunisian S. glaucus. They were also polymorphic for the same set of cpDNA haplotypes present in Tunisian S. glaucus.
  • • We conclude that the Sicilian Senecio is a variant form of North African S. glaucus ssp. coronopifolius, which most probably dispersed to sand dunes in southern Sicily in the relatively recent past. The presence of several cpDNA haplotypes in this material indicates that there have been multiple introductions of the species to Sicily.

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