Granite Cape Flax

Taxonomy
Scientific Name
Polycarena silenoides Harv. ex Benth.
Higher Classification
Dicotyledons
Family
SCROPHULARIACEAE
Synonyms
Nycterinia selaginoides (Thunb.) Benth. var. parviflora Benth., Zaluzianskya selaginoides (Thunb.) Walp. var. parviflora (Benth.) Walp., Zaluzianskya villosa F.W.Schmidt var. parviflora (Benth.) Hiern in Fl. Cap. 4(2): 345 (1904), excluding all cited specimens (in part)
Common Names
Granite Cape Flax (e)
National Status
Status and Criteria
Critically Endangered B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v)
Assessment Date
2016/03/07
Assessor(s)
G. Laidler, D.A. Snijman & D. van der Colff
Justification
One small subpopulation (EOO 0.13 km², AOO <0.13 km²) is suspected to continue to decline due to ongoing competition from alien invasive plants.
Distribution
Endemism
South African endemic
Provincial distribution
Western Cape
Range
Lion's Head, Cape Peninsula.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Peninsula Granite Fynbos
Description
Granite slopes.
Threats
The only known population occurs within the Table Mountain National Park, but its habitat is infested with alien invasive grasses that are likely to outcompete native species. Alien grass infestations are extremely difficult to control, and stems from the reserve bordering on urban areas - a continuous source of exotic and invasive species entering indigenous fynbos vegetation. There is also ongoing degradation of granite fynbos on the slopes of Lion's Head due to too frequent fires, but it may not have such a severe impact on P. silenoides as it is an annual species.
Population

Polycarena silenoides was previously known only from a small number of historical records, and has not been seen for more than 100 years. It was thought to be possibly extinct until targeted surveys relocated a population at the type locality in 2015. This species is most likely a fire ephemeral, as it was found following a fire, but then the population could not be relocated in the following year (G. Laidler pers. comm. 2016). About 20 plants were counted in 2015, but this species is very cryptic and easily overlooked among dense vegetation, and therefore the population size may be an underestimate. The population trend is not known at this stage, but is suspected to be either fluctuating or declining.


Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Polycarena silenoides Harv. ex Benth.Critically Endangered (Possibly Extinct) Raimondo et al. (2009)
Polycarena silenoides Harv. ex Benth.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.


Helme, N.A. and Trinder-Smith, T.H. 2006. The endemic flora of the Cape Peninsula, South Africa. South African Journal of Botany 72(2):205-210.


Hilliard, O.M. 1994. The Manuleae: a tribe of Scrophulariaceae. Edinburgh University Press, Edinburgh.


Hilton-Taylor, C. 1996. Red data list of southern African plants. Strelitzia 4. South African National Botanical Institute, Pretoria.


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.


Citation
Laidler, G., Snijman, D.A. & van der Colff, D. 2016. Polycarena silenoides Harv. ex Benth. National Assessment: Red List of South African Plants version 2017.1. Accessed on 2017/08/22

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Distribution map

© G. Laidler

© G. Laidler

© G. Laidler


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