Taxonomic revision of Ceropegia sect. Huernia (Asclepiadoideae, Apocynaceae) in Saudi Arabia with three new combinations.

This study provides a taxonomic revision for Ceropegia sect. Huernia in the flora of Saudi Arabia. Forty-six quantitative and qualitative morphological characters were analysed using principal component analysis (PCA), principal coordinates analysis (PCoA) and the unweighted pairs group using mean average (UPGMA) to separate and help delimit taxa. We propose to reduce the number of species reported in Saudi Arabia from 11 to four: C. khalidbinsultanii comb. nov., C. laevis, C. lodarensis and C. macrocarpa. This study also suggested reducing two names to varietal level under C. lodarensis (var. foetidacomb. nov. and var. rubrostictacomb. nov.). A key to the species, detailed morphological descriptions, illustrations, distribution maps, ecology, etymology and preliminary conservation assessments are provided that follow IUCN criteria.