Cape Flats Quillwort

Scientific Name
Isoetes stellenbossiensis A.V.Duthie
Higher Classification
Common Names
Stellenbosch Quillwort (e)
National Status
Status and Criteria
Least Concern
Assessment Date
J.P. Roux, D. Raimondo & L. von Staden
Isoetes stellenbossiensis is a widespread and common species. It is declining across most of its range due to ongoing habitat loss and degradation, but is not yet in danger of extinction.
South African endemic
Provincial distribution
Northern Cape, Western Cape
This species occurs from the Bokkeveld Escarpment to the Cape Peninsula, and eastwards to the Agulhas Plain.
Habitat and Ecology
Major system
Major habitats
It prefers seasonally waterlogged soils and seeps on granite outcrops, more rarely on sandy soils.
This species has declined on the Cape Flats and around Stellenbosch due to historical habitat loss to urban expansion, and loss continues. In the Breede River Valley, Koue Bokkeveld, Agulhas Plain and Swartland, it is threatened by ongoing habitat loss to agricultural expansion. Many subpopulations persist on small remnants, where they are threatened by ongoing habitat degradation due to disruption of wetland flow dynamics, eutrophication and competition from alien invasive plants.

This species is still relatively common, in spite of extensive historical habitat loss on the Western Cape coastal lowlands (Crouch et al. 2011). Subpopulations are large, typically consisting of extensive colonies of several hundred to thousands of plants. A continuing decline is inferred from ongoing habitat loss and degradation.

Population trend
Localities in the northern part of this species' range may represent undescribed species (Musselman and Roux 2002).
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Isoetes stellenbossiensis A.V.DuthieNT B1ab(iii)Raimondo et al. (2009)

Cook, C.D.K. 2004. Aquatic and wetland plants of southern Africa. Backhuys Publishers, Leiden, The Netherlands.

Crouch, N.R., Klopper, R.R., Burrows, J.E. and Burrows, S.M. 2011. Ferns of southern Africa: A comprehensive guide. Struik Nature, Cape Town.

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.

Musselman, L.J. and Roux, J.P. 2002. Isoetes toximontana (Isoetaceae), a new quillwort with green megaspores from the Northern Cape of South Africa. Novon 12(4):504-507.

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.

Sieben, E.J.J. 2009. The status and distribution of vascular plants (Magnoliophyta, Lycophyta, Pteridophyta). In: W.R.T. Darwall, K.G. Smith, D. Tweddle and P. Skelton (eds.), The status and distribution of freshwater biodiversity in southern Africa (pp. 83-98), IUCN and SAIAB, Gland, Switzerland and Grahamstown, South Africa.

Roux, J.P., Raimondo, D. & von Staden, L. 2020. Isoetes stellenbossiensis A.V.Duthie. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2023/12/04

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Distribution map

© J.P. Roux

© J.E. Burrows

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