Phylogenetic relationships of Tolpis (Asteraceae: Lactuceae) based on ndhF sequence data

Abstract.

 Tolpis includes approximately 12–20 species distributed primarily in Europe, Middle East, and Africa with most species (10) confined to the Macaronesian archipelagos of the Azores, Madeira, Canary Islands, and Cape Verde Islands. Although there has been considerable effort to resolve generic circumscriptions and relationships among genera of the tribe Lactuceae, much controversy still remains regarding these taxonomic issues for Tolpis. Phylogenetic analyses of the chloroplast encoded gene ndhF were performed using 36 species from 28 genera of Lactuceae and outgroup taxa from the five other tribes of Cichorioideae. The sampling included most previously suggested generic relatives of Tolpis and seven species of Tolpis from Africa, Europe, and Macaronesia. The ndhF phylogeny indicates that Tolpis is not monophyletic because two continental species, T. capensis from south-central Africa and Madagascar and T. staticifolia from central and southeast Europe, do not occur in the strongly supported core Tolpis clade. This result is in agreement with recent suggestions based on macromorphology and palynology that these two species should be excluded from Tolpis. Tolpis capensis is sister to Taraxacum and T. staticifolia is nested within the genus Crepis. The ndhF tree also indicates that the core Tolpis clade is an isolated lineage that is not related to any of the previously suggested genera of Lactuceae. Relationships among the five examined core Tolpis species are fully resolved in the ndhF tree. The three examined island species occur in two different clades suggesting either multiple colonizations or a single origin and subsequent recolonization of the continent. Resolution of the origin of the island endemics will require additional taxon sampling and the use of more variable molecular markers.