Abstract
In this study, karyotype criteria of 27 accessions (17 taxa) of the two tribes Asclepiadeae (20 accessions) and Ceropegieae (7 accessions) from Egypt and Saudi Arabia belonging to subfamily Asclepiadoideae are described and polyploid variations are also discussed. Detailed karyotype features, i.e. total chromosome length (TCL), mean chromosome length (MCL) and karyotype asymmetry expressed as arm ratio (MAR), total form percent (TF %), intrachromosomal asymmetry (A(1)) and interchromosomal asymmetry (A(2)), are also described. Karyotype features of the studied accessions were used to assess the tribal relationships within the subfamily Asclepiadoideae to differentiate between taxa that belonging to the tribes Asclepiadeae and Ceropegieae in the light of the current systems of classification. In addition, new chromosome counts of 16 taxa or accessions are reported here for the first time.