J Syst Evol ›› 2021, Vol. 59 ›› Issue (4): 791-808.DOI: 10.1111/jse.12742

• Research Articles • Previous Articles     Next Articles

Global dispersal and diversification of the genus Schoenus (Cyperaceae) from the Western Australian biodiversity hotspot

Tammy L. Elliott1,2*, Ruan van Mazijk2, Russell L. Barrett3, Jeremy J. Bruhl4, Simon Joly5,6, Ngalirendwe Muthaphuli2, Karen L. Wilson3, and A. Muthama Muasya2,7   

  1. 1Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlarska 2, Brno 611 37, Czech Republic
    2Bolus Herbarium, Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, Cape Town 7701, South Africa
    3National Herbarium of New South Wales, Royal Botanic Gardens and Domain Trust, Mrs Macquaries Road, Sydney, NSW 2000, Australia
    4Botany and N.C.W. Beadle Herbarium, University of New England, Armidale, NSW 2351, Australia
    5Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, 4101, Sherbrooke East, Montreal, QC H1X 2B2, Canada
    6Montreal Botanical Garden, 4101, Sherbrooke East, Montreal, QC H1X 2B2, Canada
    7Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AE, United Kingdom
  • Received:2020-10-09 Accepted:2021-02-24 Online:2021-03-12 Published:2021-07-01

Abstract: The predominantly austral genus Schoenus L. is the largest genus in tribe Schoeneae and one of the ten most species-rich Cyperaceae genera, with over 150 accepted species found mostly in Australia, New Zealand, southeast Asia, and southern Africa. Here, we use data based on two nuclear and three plastid DNA regions to present one of the most comprehensive phylogenetic reconstructions of a genus in Cyperaceae to date, covering over 70% of described species of Schoenus. After recent taxonomic realignments in the last 4 years have both added and removed species from the genus, we show that Schoenus is now monophyletic. In addition, our results indicate that Schoenus originated in Western Australia in the Paleocene and eventually dispersed to surrounding continents, but rarely back. The diversification rate of the genus appears to have slightly decreased over time, and there has not been an increase associated with the establishment of the Cape clade endemic to the sclerophyllous fynbos vegetation type, such as has been reported in other plant lineages endemic to the Cape region. These results will serve as a template to understanding the complex patterns of genome size evolution and to untangle drivers of diversification in this genus.

Key words: ancestral area reconstruction, austral, biogeography, Cape clade, dispersal, diversification, fynbos, kwongan, phylogenetics, sclerophyllous