On my second attempt keeping O. dummeri, it rewards me with strickingly beautiful flowers. Perhaps it is a more heat tolerant clone after going through a rot or thrive selection process over Southern Taiwan's hot 36 C summers. According to Monograph of Orbea and Ballyanthus by P. V. Bruyns in Systematic Botany Monographs Vol.63, it is a species higher and drier parts of Kenya, and other neighbouring countries of the Rift Valley occuring from 950 - 1600m. The plant in my first failed attempt came from chiller greenhouse of the West, and it quickly perished.
Over the last couple of years, i come to realized that stapeliads are not so difficult to keep if they can tolerate heat in the high 30Cs. Should they look limp and a bit desiccated after their peak growth or flowering season... let them be. They just need a dry rest with a bit of water just to keep them from unrecoverable desiccation. During this period, look out signs of deadly pest like spider mites. Spider mites can easily reduced plants to sad resting state look! When new growth starts, water & fertilize. And if it is a tempermental species take cuttings and keep an extra pot!