A worldwide molecular phylogeny and classification of the leafy spurges, Euphorbia subgenus Esula (Euphorbiaceae)
- 1 April 2013
- Vol. 62 (2), 316-342
- https://doi.org/10.12705/622.3
Abstract
The leafy spurges, Euphorbia subg. Esula, make up one of four main lineages in Euphorbia. The subgenus comprises about 480 species, most of which are annual or perennial herbs, but with a small number of dendroid shrubs and nearly leafless, pencil–stemmed succulents as well. The subgenus constitutes the primary northern temperate radiation in Euphorbia. While the subgenus is most diverse from central Asia to the Mediterranean region, members of the group also occur in Africa, in the Indo–Pacific region, and in the New World. We have assembled the largest worldwide sampling of the group to date (273 spp.), representing most of the taxonomic and geographic breadth of the subgenus. We performed phylogenetic analyses of sequence data from the nuclear ribosomal ITS and plastid ndhF regions. Our individual and combined analyses produced well–resolved phylogenies that confirm many of the previously recognized clades and also establish a number of novel groupings and placements of previously enigmatic species. Euphorbia subg. Esula has a clear Eurasian center of diversity, and we provide evidence for four independent arrivals to the New World and three separate colonizations of tropical and southern Africa. One of the latter groups further extends to Madagascar and New Zealand, and to more isolated islands such as Réunion and Samoa. Our results confirm that the dendroid shrub and stem–succulent growth forms are derived conditions in E. subg. Esula. Stem–succulents arose twice in the subgenus and dendroid shrubs three times. Based on the molecular phylogeny, we propose a new classification for E. subg. Esula that recognizes 21 sections (four of them newly described and two elevated from subsectional rank), and we place over 95% of the accepted species in the subgenus into this new classification.This publication has 34 references indexed in Scilit:
- Phylogenetics, morphological evolution, and classification of Euphorbia subgenus EuphorbiaTaxon, 2013
- Phylogenetics of the Chamaesyce clade (Euphorbia, Euphorbiaceae): Reticulate evolution and long‐distance dispersal in a prominent C4 lineageAmerican Journal of Botany, 2011
- Further support for the phylogenetic relationships within Euphorbia L. (Euphorbiaceae) from nrITS and trnL–trnF IGS sequence dataÖsterreichische botanische Zeitschrift, 2010
- Bayesian island biogeography in a continental setting: the Rand Flora caseBiology Letters, 2010
- Evidence for a vicariant origin of Macaronesian–Eritreo/Arabian disjunctions in Campylanthus Roth (Plantaginaceae)Molecular Phylogenetics and Evolution, 2010
- jModelTest: Phylogenetic Model AveragingMolecular Biology and Evolution, 2008
- RAxML-VI-HPC: maximum likelihood-based phylogenetic analyses with thousands of taxa and mixed modelsBioinformatics, 2006
- MAFFT version 5: improvement in accuracy of multiple sequence alignmentNucleic Acids Research, 2005
- Using molecular phylogenies to test phytogeographical links between East/South Africa–Southern Arabia and the Macaronesian islands—a review, and the case of Vierea and Pulicaria section Vieraeopsis (Asteraceae)Taxon, 2004
- Karyological evolution and molecular phylogeny in Macaronesian dendroid spurges ( Euphorbia subsect. Pachycladae )Österreichische botanische Zeitschrift, 2002