Dioscorea brownii

Dioscorea brownii was first discovered in 1883, and since then it has been rarely collected. Historical records are from a wide area stretching from the Richmond district in southern KwaZulu-Natal to Umtata in the Eastern Cape. These records, however, have very imprecise locality descriptions, and many have never been relocated. Since the 1970s, the species was known only from a small area on state land around Weza, southern KwaZulu-Natal. Here the species remains on small remnants of mistbelt grassland. Three small, isolated subpopulations are currently known, the largest one consisting of around 200 mature individuals, and the other two with between 10 and 50 plants. A fourth subpopulation, recorded by the local conservation authority in the same area, is likely to still exist, but survey data lacks an estimate of the subpopulation size. Recently, another small subpopulation was discovered about 80 km north of Ngele, in the Richmond district, where it was last recorded in 1946. About 100 plants occur in scattered, small clumps in mistbelt grassland fragmented by timber plantations.

This species is easily overlooked within its grassland habitat, and may be under-sampled. However, with less than 30% of its habitat remaining intact, it is unlikely that many more subpopulations exist, and all are likely to be small and confined to isolated grassland fragments. Remaining known subpopulations require ongoing monitoring. Estimating the global population size is difficult, but it is likely to be small. All known subpopulations consist of fewer than 200 mature individuals, and therefore it is unlikely that the population size exceeds 2,500 mature individuals. A present the known population numbers around 400 mature individuals.

This species' extent of occurrence (EOO) is very uncertain: historical records are from an area of over 10 000 km². Current known occurrences of this species are, however, confined to an area of 500-6,941 km².