The monogeneric family is placed in the Rhamnales in the system of ENGLER and is closely allied to the Vitaceae, sometimes considered as a subfamily or tribe of that family. Distinguished from the Vitaceae by the development of a complex staminodial tube, by the presence of one ovule in each locule of the ovary. Pollen is also distinct from that in Vitaceae, supporting the segregation into a separate family. Seed and embryo features and the presence of pearl glands on the vegetative organs indicate a very close affinity with the Vitaceae but not to other families.