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Scientific Name | Sorocephalus clavigerus (Salisb. ex Knight) Hutch. |
Higher Classification | Dicotyledons |
Family | PROTEACEAE |
Synonyms | Sorocephalus rupestris (Salisb. ex Knight) E.Phillips |
Common Names | Erect Clusterhead (e) |
National Status |
Status and Criteria | Endangered B1ab(iii,v)+2ab(iii,v); C2a(i) |
Assessment Date | 2020/08/13 |
Assessor(s) | A.G. Rebelo, D. Raimondo & N.A. Helme |
Justification | Sorocephalus clavigerus has a restricted range, with an extent of occurrence (EOO) of 265 km², and an area of occupancy (AOO) of 23 km². Subpopulations are small, mostly consisting of fewer than 10 plants, and only three subpopulations have between 10 and 100 mature individuals. The population consists of fewer than 2500 plants, is severely fragmented and continues to decline due to competition with invasive alien plants and also for unknown reasons. It therefore qualifies for listing as Endangered under criteria B and C. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Western Cape |
Range | This species has a limited distribution in mountains of the Western Cape Province in South Africa, where it occurs from the Hottentots Holland to Kogelberg mountains. It also occurred historically in the Kleinrivier Mountains but is now extinct on this range. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Kogelberg Sandstone Fynbos, Hawequas Sandstone Fynbos |
Description | It grows on well-drained, stony or sandy soils in sandstone fynbos, 450-1500 m. Mature individuals are killed by fires, and only seeds survive. Seeds are released after ripening, and dispersed by ants to their underground nests, where they are protected from predation and fire. It is pollinated by insects. |
Threats |
| This species' habitat is currently not transformed, however invasive alien plant species pose a significant threat. Its habitat is currently experiencing ongoing decline as a result of the spread of invasive hakea and pine species. |
Population |
This species occurs as naturally fragmented subpopulations that are all small in size, with most subpopulations consisting of fewer than 10 plants. The subpopulations at Moordenaarskop, Spinnekopnes, and Paardeberg have between 10 and 100 mature individuals. The population is considered to be severely fragmented and is declining due to competition with invasive alien plant species. Subpopulations at Kleinrivier mountains have not been relocated since 1960 and this species is suspected to be extinct there, the cause of decline is not known.
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Population trend | Decreasing |
Conservation |
| The entire range of this species falls either in the Hottentot Holland Nature Reserve or the Kogelberg Biosphere Reserve. |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Sorocephalus clavigerus (Salisb. ex Knight) Hutch. | EN B1b(i,ii,iii,iv,v)c(iv)+2b(i,ii,iii,iv,v)c(iv); C2a(i); D | Raimondo et al. (2009) | |
Bibliography |
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.
Manning, J.C. and Goldblatt, P. 2012. Plants of the Greater Cape Floristic Region 1: The Core Cape Flora. Strelitzia 29. South African National Biodiversity 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.
Rebelo, T. 2001. Sasol Proteas: A field guide to the proteas of southern Africa. (2nd ed.). Fernwood Press, Vlaeberg, Cape Town.
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Citation |
| Rebelo, A.G., Raimondo, D. & Helme, N.A. 2020. Sorocephalus clavigerus (Salisb. ex Knight) Hutch. National Assessment: Red List of South African Plants version . Accessed on 2025/05/08 |
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