Format: ORAL

Maria-Anna Vasile1,*, Tim Bhnert1, Julius Jeiter2, Maximilian Weigend1

1 Bonn Institute for Organismic Biology (BIOB), Plant Biodiversity Section, University of Bonn, Meckenheimer Allee 170, 53115 Bonn, Germany 2 Chair of Botany, Faculty of Biology, TUD Dresden University of Technology, 01062 Dresden, Germany * email: m.vasile@uni-bonn.de

Boraginales are a subcosmopolitan order with ca. 2,700 species recognized in 11 families. We re-analyzed relationships using the Angiosperms353 probe set. In addition to the Angiosperms353 nuclear gene data from 109 Boraginales accessions available in PAFTOL, phylogenomic data from 161 samples were generated, collectively representing all Boraginales families and approximately 84% of genus diversity. The results are consistent with previous phylogenetic studies, with some novelties and overall better resolution. Well-resolved species trees are retrieved with consistently high support for both data sets used (exons and supercontigs) and both analyses implemented (concatenation and multi-locus species tree estimation approach). Among the most important findings, Lennoaceae are found nested in Ehretiaceae and we propose their inclusion in Ehretiaceae. The tribal relationships of the highly diverse Boraginaceae subfam. Cynoglossoideae are fully resolved for the first time. Residual ambiguities remain: Codonaceae are found as basal branch in Boraginales I (sister to [Wellstediaceae and Boraginaceae]) in the exonic data set, in agreement with previous studies, but they are retrieved as basal branch of Boraginales II in reconstructions based on exons and introns. Also, the sister relationship of Namaceae and Hydrophyllaceae is not clear, probably due to limited sampling especially in Nama. Similarly, tribe Cynoglosseae was summarily sampled and intergeneric relationships are not at present fully resolved. Overall, the results highlight the effectiveness of the target enrichment probe set for understanding the evolutionary history of Boraginales and pave the way for resolving remaining taxonomic issues and a comprehensive study of the evolution of group-specific morphological traits. Our studies on the internal ovary architecture using scanning electron microscopy and micro-computed tomography reveal that changes in placentation and ovule number are key characters in the macroevolution and divergence of Boraginales families. Combining highly resolved phylogeny with critical morphological analyses promises a deep understanding of evolution trajectories in Boraginales.