Rhytidocaulon macrolobum Lavr.Rhytidocaulon macrolobum is a member of the Asclepiadiaceae from South Western Arabia. Like many of the plants of this family which grow in Arabia and East Africa it is not easy to cultivate. It will not tolerate low temperatures or high humidity, frequently succumbing to fungal attacks if kept in sub-optimal conditions. We managed to keep this seedling grown specimen alive for a few years by growing it indoors on a radiator shelf rather than in the greenhouse, however we did eventually lose it. The flowers are quite small (1.5cm diameter) but beautifully marked if viewed under a hand lens. Not being experts on the Asclepiadiaceae we would not guarantee the specific name.