0000000000388746
AUTHOR
Bertil Nordenstam
Patterns and causes of incongruence between plastid and nuclear Senecioneae (Asteraceae) phylogenies
One of the longstanding questions in phylogenetic systematics is how to address incongruence among phylogenies obtained from multiple markers and how to determine the causes. This study presents a detailed analysis of incongruent patterns between plastid and ITS/ETS phylogenies of Tribe Senecioneae (Asteraceae). This approach revealed widespread and strongly supported incongruence, which complicates conclusions about evolutionary relationships at all taxonomic levels. The patterns of incongruence that were resolved suggest that incomplete lineage sorting (ILS) and/or ancient hybridization are the most likely explanations. These phenomena are, however, extremely difficult to distinguish beca…
An ITS phylogeny of tribe Senecioneae (Asteraceae) and a new delimitation of Senecio L.
Senecioneae is the largest tribe ofAsteraceae, comprised ofca. 150 genera and 3,000 species. Approximately one-third of its species are placed in Senecio, making it one of the largest genera of flowering plants. Despite considerable efforts to classify and understand the striking morphological diversity in Senecioneae, little is known about its intergeneric relationships. This lack ofphylogenetic understanding is predominantly caused by conflicting clues from morphological characters, the large size ofthe tribe, and the absence of a good delimitation of Senecio. Phylogenetic analyses of nrITS and plastid DNA sequence data were used to produce a hypothesis of evolutionary relationships in Se…
The identity and geographical distribution of Jacobaea vulgaris subsp. gotlandica , supposedly endemic to Gotland and Öland (Sweden)-the importance of multiple intraspecific samples
The identity of Jacobaea vulgaris Gaertn. subsp. gotlandica (Neum.) B. Nord., hitherto considered an endemic to the Swedish islands Oland and Gotland, was investigated using nrITS and trnT-trnL intergenic spacer sequences and a broad sample of species and accessions particularly of J. vulgaris. We found that J. vulgaris subsp. gotlandica is a distinct evolutionary lineage more widespread in Europe than previously thought and may be a southeastern European steppe floristic element with outliers on the large Baltic islands. Our entirely unexpected findings underline the need of multiple intraspecific sampling in species-level phylogenetic studies.