Diversification of the old world Salsoleae s.l. (Chenopodiaceae): Molecular phylogenetic analysis of nuclear and chloroplast data sets and a revised classification

Abstract

A first comprehensive phylogenetic analysis of tribe Salsoleae s.l. (Salsoloideae: Chenopodiaceae) is presented based on maximum parsimony and maximum likelihood analysis of nuclear ribosomal internal transcribed spacer and chloroplast psbB-psbH DNA sequences. Our data strongly support (1) the sister relationship of Camphorosmeae to the Salsoleae s.l.; (2) splitting of Salsoleae s.l. into two monophyletic tribes, Salsoleae s.s. and Caroxyloneae tribus nova; (3) the current status of most monotypic or oligotypic genera in Salsoleae; and (4) polyphyly of the Botschantzev and Freitag (among others) circumscriptions of Salsola, which falls into 10 (on average) monophyletic genera/lineages. Three well-supported genera are described as new (Pyankovia, Kaviria, and Turania), and four previously described genera are resurrected (Caroxylon, Climacoptera, Kali, and Xylosalsola). Salsola s.s. include a group of central and southwest Asian and north African species that consists of Salsola sect. Salsola s.s., Salsola sect. Caroxylon subsect. Coccosalsola, Salsola sect. Obpyrifolia, Fadenia, Hypocylix, Seidlitzia, and Darniella. All species of tribe Caroxyloneae investigated so far have C4 photosynthesis of the NAD-malic enzyme subtype, while the majority of the species of Salsoleae s.s. are known to be of the NADP-malic enzyme subtype. © 2007 by The University of Chicago. All rights reserved.