The Stapelia genus no longer exists. All of its species have been reclassified as species of Ceropegia. I don't know where you found your information, Ursula, but the Catalogue of Life clearly lists S. gigantea as a synonym. It was a fairly recent change, so you may have been looking at an outdated CoL entry.
http://www.catalogueoflife.org...
Also, I never received notification that you were summoning me in this thread. I see that you edited that post. If you added my name in an edit, the summons would not work.