A genus of plants that are wholly parasitic on vines of the family Vitaceae. The flowers are showy and huge (up to 1 m diameter in R. arnoldii). They have 4–6 fleshy tepals, fused at the base, stamens fused as a ring, and the ovary inferior and immersed in a central column, smelling of carrion, and fly-pollinated. It is a prized medicine. There are about 13 species occurring in western Malaysia.
Subjects: Plant Sciences and Forestry.