The material from Tanzania has larger and darker corollas than the material from Uganda. It also has longer filaments. But I do not find the populations sufficiently different to recognise two subspecies and looking further west, where other variation patterns occur, the two areas are more or less connected by the populations in Rwanda, Burundi and eastern Congo. There is therefore a real possibility of the species occurring in W Tanzania. Subsp. zambiense Champl. from NW Zambia and Congo has a longer corolla tube with the ring of hairs higher up. This could also occur in SW Tanzania.