Phylogenetic Relationships among the Primarily North American Genera of Cichorieae (Compositae) based on Analysis of 18S–26S Nuclear rDNA ITS and ETS Sequences

Abstract

Abstract Phylogenetic analyses of internal transcribed spacer (ITS), external transcribed spacer (ETS), and 5.8S gene sequences of 18S–26S nuclear rDNA from all 23 genera of Cichorieae with centers of diversity in North America (and Picrosia from South America) show that all but three of the genera (Glyptopleura, Krigia, and Phalacroseris) belong to a series of seven clades that are well supported by bootstrap values >90%. Phalacroseris, endemic to California, with a single species (P. bolanderi), is sister to a well-supported (>95% bootstrap) clade that includes all other principally North American genera (plus Picrosia). The seven clades with major support and their component genera are: 1) the Lygodesmia Clade: Chaetadelpha, Lygodesmia, and Shinnersoseris; 2) the Pinaropappus Clade: Marshalljohnstonia and Pinaropappus; 3) the Pyrrhopappus Clade: Picrosia and Pyrrhopappus; 4) the Microseris Clade: Agoseris, Microseris, Nothocalais, Stebbinsoseris, and Uropappus; 5) the Stephanomeria Clade: Munzothamnus,...