Hybridization and Asymmetric Introgression after Secondary Contact in Two Tropical African Climber Species, Haumania danckelmaniana and Haumania liebrechtsiana (Marantaceae)

Premise of research. Interspecific hybridization is frequently observed between closely related plant species with overlapping distribution ranges, especially in zones of secondary contact after isolation in different refugia. Although well studied in temperate regions, interspecific hybridization is little documented in tropical regions, where it may be frequent in areas with high species diversity. To bridge this gap, we investigate hybridization in two closely related climber species from the genus Haumania (Haumania danckelmaniana and Haumania liebrechtsiana) originating from Gabon/Cameroon and the Democratic Republic of Congo, respectively, and co-occurring in Northern Gabon. The aim of this study was to genetically quantify and qualify the degree of hybridization between these species in their area of distributional overlap by including for the first time morphological intermediates.Methodology. We investigated 265 individuals from nine sites (seven sites containing both species) by genotyping seven...