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Scientific Name | Diosma guthriei P.E.Glover |
Higher Classification | Dicotyledons |
Family | RUTACEAE |
National Status |
Status and Criteria | Near Threatened B1ab(ii,iii,iv,v)+2ab(ii,iii,iv,v) |
Assessment Date | 2012/08/16 |
Assessor(s) | D. Raimondo, N.A. Helme, T. Trinder-Smith & V. Zikishe |
Justification | EOO 5311 km², between 20 and 30 remaining locations are threatened by habitat loss to coastal development, limestone mining, and competition from alien invasive plants. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Western Cape |
Range | Agulhas Plain between Bredasdorp, Struisbaai and Arniston and between Paternoster and Jacobsbaai. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Overberg Dune Strandveld, Langebaan Dune Strandveld, Saldanha Limestone Strandveld, Saldanha Flats Strandveld, Saldanha Granite Strandveld, Central Ruens Shale Renosterveld, De Hoop Limestone Fynbos, Agulhas Limestone Fynbos, Elim Ferricrete Fynbos, Agulhas Sand Fynbos |
Description | Limestone hills, tertiary limestone deposits. |
Threats |
| Plants on the Vredenburg Peninsula as well as the Agulhas Plain are predominantly threatened by habitat loss to coastal development. In addition, much of the Agulhas Plain remains densely infested with alien invasive plants, although efforts have been made to clear alien plants within the Agulhas National Park. Much of this species' habitat on the Vredenburg Peninsula is on properties owned by a cement manufacturer, and is earmarked for limestone mining. |
Population |
This species is locally common, often dominant, in coastal limestone fynbos.
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Population trend | Decreasing |
Notes |
| Diosma guthriei was originally described from the Agulhas Plain, but in 1982, plants apparently belonging to this species were found on the Vredenburg Peninsula (identification confirmed by Ion Williams, Diosma expert), representing a disjunction of 250 km, which is most unusual in the Rutaceae. It is possible that the Vredenburg collections represent a separate taxon, however until DNA studies are undertaken to confirm this, the collections are treated as one species. |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Diosma guthriei P.E.Glover | VU B1ab(ii,iii,v) | 2012.1 | | Diosma guthriei P.E.Glover | VU B1ab(ii,iii,v) | Raimondo et al. (2009) | | Diosma guthriei P.E.Glover | Data Deficient | Victor (2002) | | Diosma guthriei P.E.Glover | Insufficiently Known | 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.
Victor, J.E. 2002. South Africa. In: J.S. Golding (ed), Southern African plant Red Data Lists. Southern African Botanical Diversity Network Report 14 (pp. 93-120), SABONET, Pretoria.
Williams, I. 1982. Studies in the genera of the Diosmeae (Rutaceae): 14. A review of the genus Diosma L. Journal of South African Botany 48(3):329-407.
Zietsman, M.M. 2003. Phytosociological study of Andrew's field and the Tsaba-Tsaba nature reserve, Bredasdorp distict, Western Cape. Unpublished M.Sc., University of Pretoria, Pretoria.
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Citation |
| Raimondo, D., Helme, N.A., Trinder-Smith, T. & Zikishe, V. 2012. Diosma guthriei P.E.Glover. National Assessment: Red List of South African Plants version . Accessed on 2025/04/14 |
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