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Scientific Name | Geissorhiza geminata E.Mey. ex Baker |
Higher Classification | Monocotyledons |
Family | IRIDACEAE |
National Status |
Status and Criteria | Endangered B1ab(ii,iii,iv,v)+2ab(ii,iii,iv,v); C2a(i) |
Assessment Date | 2023/05/29 |
Assessor(s) | P. Goldblatt, D. Raimondo & N.A. Helme |
Justification | This species has an extent of occurrence (EOO) of 4253-4415 km², and an area of occupancy (AOO) of 48-56 km². It is known from between ten and 12 locations and the population is severely fragmented. There are fewer than 2500 mature individuals in the population and no subpopulation has been recorded to have more than 250 individuals. It has lost over 50% of known subpopulations to vineyards, orchards and olive cultivation over the past 100 years. This wetland habitat specialist continues to be threatened by habitat loss to crop cultivation and associated wetland drainage as well as encroachment by invasive aliens plants. It is therefore listed as Endangered under criteria B and C. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Western Cape |
Range | A narrow endemic to the Western Cape province of South Africa, extending from the Koue Bokkeveld and Upper Tulbagh Valley in the north to Brandvlei near Worcester in the south. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Breede Shale Fynbos, Kouebokkeveld Shale Fynbos, Breede Sand Fynbos, Breede Alluvium Fynbos, Kouebokkeveld Alluvium Fynbos |
Description | It is semi-aquatic, occurring in sandy marshes, ponds and vleis, often in standing water. |
Threats |
| This species has lost more than 50% of its former habitat to vineyards, orchards and olive cultivation, and the drainage of wetlands is an ongoing threat. Much of this species' remaining habitat is invaded by alien plants, particularly Acacia saligna. |
Population |
Field surveys undertaken since 2010, documented via the Custodians of Rare and Endangered Wildflowers programme and iNaturalist provide subpopulation sizes for seven of the ten extant subpopulations. These all show that subpopulations are small (typically fewer than 100 plants) and isolated from one another due to their specificity for wetland habitats. The only subpopulation recorded to have more than 100 individuals is at Theuniskraal farm north of Tulbagh, where there are less than 250 mature individuals. The population is declining due to ongoing habitat loss to agriculture and degradation as a result of invasive alien plants.
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Population trend | Decreasing |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Geissorhiza geminata E.Mey. ex Baker | EN B1ab(ii,iii,iv,v) | Raimondo et al. (2009) | | Geissorhiza geminata E.Mey. ex Baker | Vulnerable | Hilton-Taylor (1996) | | Geissorhiza geminata E.Mey. ex Baker | Uncertain | Hall et al. (1980) | |
Bibliography |
Goldblatt, P. 1985. Systematics of the southern African genus Geissorhiza (Iridaceae-Ixioideae). Annals of the Missouri Botanical Garden 72(2):277-447.
Goldblatt, P. and Manning, J.C. 2000. Cape Plants: A conspectus of the Cape Flora of South Africa. Strelitzia 9. National Botanical Institute, Cape Town.
Goldblatt, P. and Manning, J.C. 2020. Iridaceae of southern Africa. Strelitzia 42. South African National Biodiversity Institute, Pretoria.
Hall, A.V., De Winter, M., De Winter, B. and Van Oosterhout, S.A.M. 1980. Threatened plants of southern Africa. South African National Scienctific Programmes Report 45. CSIR, Pretoria.
Hilton-Taylor, C. 1996. Red data list of southern African plants. Strelitzia 4. South African National Botanical Institute, Pretoria.
Raimondo, D., von Staden, L., Foden, W., Victor, J.E., Helme, N.A., Turner, R.C., Kamundi, D.A. and Manyama, P.A. 2009. Red List of South African Plants. Strelitzia 25. South African National Biodiversity Institute, Pretoria.
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Citation |
| Goldblatt, P., Raimondo, D. & Helme, N.A. 2023. Geissorhiza geminata E.Mey. ex Baker. National Assessment: Red List of South African Plants version . Accessed on 2024/09/08 |
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