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Scientific Name | Serruria williamsii Rourke |
Higher Classification | Dicotyledons |
Family | PROTEACEAE |
Common Names | King Spiderhead (e) |
National Status |
Status and Criteria | Endangered B1ab(ii,iii,v)+2ab(ii,iii,v) |
Assessment Date | 2019/02/04 |
Assessor(s) | A.G. Rebelo & D. Raimondo |
Justification | Serruria williamsii is a range restricted species with an extent of occurrence (EOO) of 28 km², and an area of occupancy (AOO) of 16 km². The population is declining at two locations due to too frequent fires, habitat loss to protea cultivation and competition with invasive alien plant species. It therefore qualifies for listing as Endangered under criterion B. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Western Cape |
Range | This species occurs in the Riviersonderend Mountains, in the Western Cape Province of South Africa. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | North Sonderend Sandstone Fynbos |
Description | It grows in sandstone fynbos, 900-1100 m. Mature individuals are killed by fires, and only seeds survive. Seeds are relased after ripening, and dispersed by ants to their underground nests, where they are protected from predation and fire. It is pollinated by insects. |
Threats |
| The main threats to Serruria williamsii are too frequent fires, agricultural activities (protea orchards) and habitat degradation as a result of the spread of invasive alien plant species. Two historically known subpopulations have been lost most likely due to incorrect fire management. |
Population |
Known from four subpopulations, two (Poesjenels River and Jonaskop) are historical records and the subpopulations have not been observed again since 1971. It is extant at Dwarsrivier where there is a small subpopulation of fewer than 100 plants and at Groottorren where several hundred plants occur over a 3 km range. The population is declining due to competition with invasive alien plants.
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Population trend | Decreasing |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Serruria williamsii Rourke | EN B1ac(iv)+2ac(iv) | Raimondo et al. (2009) | | Serruria williamsii Rourke | Rare | Hilton-Taylor (1996) | |
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.
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 |
| Rebelo, A.G. & Raimondo, D. 2019. Serruria williamsii Rourke. National Assessment: Red List of South African Plants version . Accessed on 2025/04/14 |
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