Taxonomic revision of Ceropegia sec. Huernia (Asclepiadoideae – Apocynaceae) in Saudi Arabia with four new combinations

This study provides a taxonomic revision for Ceropegia sec. Huernia in the flora of Saudi Arabia. Forty-eight 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 proposed to reduce the number of names reported in Saudi Arabia from 11 to four species: C. arabica comb. nov. , C. Khalidbinsultanii comb. nov. , C. laevis and C. lodarensis . This study also suggested reducing two of Plowes’ new names to a variety level under  C. lodarensis (var. foetida  comb. nov.  and var. rubrosticta   comb. nov. ). A key to the species, detailed morphological descriptions, illustrations, distribution maps, ecology, etymology and preliminarily conservation assessments following IUCN criteria are provided.