Oedera rotundifolia

Taxonomy
Scientific Name
Oedera rotundifolia (Less.) N.G.Bergh
Higher Classification
Dicotyledons
Family
ASTERACEAE
Synonyms
Relhania rotundifolia Less.
National Status
Status and Criteria
Endangered B1ab(iii)+2ab(iii)
Assessment Date
2011/06/10
Assessor(s)
D. Raimondo & N.A. Helme
Justification
This species has an extent of occurrence (EOO) of 43 km² and is known from two locations. It has lost 50% of its recorded locations and over 80% of its former habitat to crop cultivation and severe alien plant infestations. Subpopulations are not considered severely fragmented as over 90% of the population occurs in Riverlands Nature Reserve. Both the subpopulation at Riverlands and the one south of Hopefield are experiencing continuing decline in habitat quality as a result of encroachment from invasive alien acacias and inappropriate fire management. It is therefore assessed as Endangered under criterion B.
Distribution
Endemism
South African endemic
Provincial distribution
Western Cape
Range
It is found from Malmesbury to Hopefield.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Atlantis Sand Fynbos, Hopefield Sand Fynbos
Description
Plants grow on seasonally wet, sandy flats, 100-150 m.
Threats
Crop cultivation in combination with dense infestations of alien plants have led to two of the four known subpopulations going extinct. The subpopulation at Hopefield is threatened by invasive alien acacias. The subpopulation at Riverlands, particularly stands on the western reserve boundary are also threatened by invasive aliens. Too frequent fires are a potential threat to the largest subpopulation at Riverlands.
Population

This species was reduced to a single population because of destruction of its habitat. It was thought to be extinct after 1932 until its rediscovery in 1978 at Riverlands Nature Reserve. The recent discovery by N. Helme of a subpopulation near Hopefield provides hope that there may still be other small remaining subpopulations occurring in remnant lowland sand fynbos between Hopefield and Riverlands. The Riverlands subpopulation consists of a number of stands of individuals numbering at least 1000. The Hopefield subpopulation is much smaller, with only 40 individuals.


Population trend
Decreasing
Conservation
It is conserved at Riverlands Nature Reserve.
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Relhania rotundifolia Less.CR B1ab(iii)+2ab(iii)Raimondo et al. (2009)
Relhania rotundifolia Less.Endangered Hilton-Taylor (1996)
Relhania rotundifolia Less.Endangered Hall et al. (1980)
Bibliography

Bremer, K. 1976. The genus Relhania (Compositae). Opera Botanica 40:1-85.


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.


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.


Stafford, G.I., Wikkelso, M.J., Nancke, L., Jager, A.K., Moller, M. and Ronsted, N. 2016. The first phylogenetic hypothesis for the southern African endemic genus Tulbaghia (Amaryllidaceae, Allioideae) based on plastid and nuclear DNA sequences. Botanical Journal of the Linnean Society 181:156–170.


Citation
Raimondo, D. & Helme, N.A. 2011. Oedera rotundifolia (Less.) N.G.Bergh. National Assessment: Red List of South African Plants version . Accessed on 2025/04/14

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Distribution map

© C. Burgers

© I. Ebrahim


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