Phylogenetic relationships in subtribe Scorzonerinae (Asteraceae: Cichorioideae: Cichorieae) based on ITS sequence data

Subtribe Scorzonerinae of tribe Lactuceae (Asteraceae: Cichorioideae) appears to be well supported as monophyletic; however, generic circumscription and relationships within the group have been problematic. To investigate the monophyly and circumscription of the recognized genera and their intergeneric relationships, we conducted a phylogenetic analysis of subtribe Scorzonerinae using ITS sequence data. Our results reveal that most genera, including Tragopogon, Epilasia, Podospermum, Koelpinia, and Lasiospora, are monophyletic. The monotypic Pterachaenia and Tourneuxia are distinct lineages within Scorzonerinae. The monotypic Geropogon, which has often been included in Tragopogon, is phylogenetically removed from the highly supported Tragopogon clade. In contrast, Scorzonera is clearly not monophyletic, with species of the genus appearing in multiple clades with other genera. Scorzonera purpurea is weakly supported as the sister to Podospermum. Scorzonera austriaca is sister to Takhtajaniantha and may represent one ancestral parent of this monotypic polyploid genus. Species of Scorzonera sections Tuberosae, Vierhapperia, Nervosae, and Pulvinares form a clade with the genus Lasiospora. Scorzonera sections Pulvinares, Tuberosae, and Foliosae are clearly not monophyletic. Some non-DNA characters (e.g., achene morphology) generally agree with the clades recognized by ITS sequence data. However, our analyses also show that traditionally important morphological and karyological characters have multiple origins in Scorzonerinae.