Lectotypes are selected for the following names in the Apocynaceae from the Arabian Peninsula: Adenium arabicum Balf.f., Adenium obesum (Forssk.) Roem. & Schultes, Caralluma adenensis (Deflers) A.Berger, Cryptolepis intricata (Balf.f.) Venter, Cryptolepis volubilis (Balf.f.) O.Schwartz, Kanahia laniflora (Forssk.) R.Br., Leptadenia arborea (Forssk.) Schweinf., Marsdenia robusta Balf.f., Rhazya stricta Decne. and Tylophora yemensis Deflers. For Secamone socotrana Balf.f., it is noted that a previous citation of a holotype is rather an effective designation of a lectotype. Neotypes are selected for Caralluma hexagona var. septentrionalis Lavranos & L.E.Newton, Glossonema boveanum (Decne.) Decne., Leptadenia pyrotechnica (Forssk.) Decne. and Orbea chrysostephana (Deflers) Bruyns.

Within Rhytidocaulon macrolobum Lavranos, which is a widespread stapeliad in Saudi Arabia and in the Yemen, the subspecies minimum Meve & Collenette is described as new. This taxon is restricted to SW Saudia Arabia; it can be easily recognized by its miniature flowers, which are conspicuously smaller than the diameter of the stems, and by its bright-coloured corona.