Changes in succulent Cynanchum species are needed for the Flora of Somalia account of Apocynaceae subfamily Asclepiadoideae.  The following changes are proposed within the tribe Asclepiadeae, subtribe Cynanchinae.  Cynanchum viminale subsp. crassicaule, another subspecific taxon in the C. viminale complex, is described as new based on morphological, ecological and molecular evidence. Its chromosome number is specified with 2n=22.  The new combination Cynanchum viminale subsp. stipitaceum is proposed and Sarcostemma andongense Hiern is recognized as a new synonym to C. viminale subsp. stipitaceum.