Phylogenomics of the holoparasitic plant genus Hydnora (Hydnoraceae)

Abstract Hydnora is a highly unusual genus of holoparasitic plants in the family Hydnoraceae comprising 10 species across Africa and the Middle East. Species concepts and relationships within the genus have historically been poorly defined, in part due to a paucity of morphological characters available for species delimitation. Here, we present the most comprehensively sampled nuclear phylogenomic study of Hydnora to date. We employ the Angiosperms353 target capture approach, using 34 nuclear loci to generate the species tree. Our results provide strong molecular support for all four recently proposed subgenera of Hydnora , demonstrating that even a limited set of morphological traits can be used to delimit lineages within the genus. We estimate ancestral states for these taxonomically informative characters within the Hydnoraceae and provide molecular evidence to clarify some of the long-standing taxonomic uncertainty within the widespread Hydnora abyssinica complex. We analyse gene tree discordance in the results and discuss our results in the context of these conflicting studies. The phylogenetic hypotheses presented here are the most widely sampled to date, and provide a framework for future ecological and evolutionary research into this enigmatic family of parasitic plants.