Taxonomy
Scientific Name
Disa longifolia Lindl.
Higher Classification
Monocotyledons
Family
ORCHIDACEAE
National Status
Status and Criteria
Vulnerable D2
Assessment Date
2012/09/03
Assessor(s)
L. von Staden
Justification
A very rare habitat specialist known from fewer than five locations. It has experienced losses of subpopulations due to dam construction and agriculture in the past. Although not currently declining, this species is potentially threatened by invasive alien plants, and habitat loss to dam construction.
Distribution
Endemism
South African endemic
Provincial distribution
Western Cape
Range
Piketberg to the Hex River Mountains and Caledon.
Habitat and Ecology
Major system
Terrestrial
Major habitats
South Hex Sandstone Fynbos, North Hex Sandstone Fynbos, Winterhoek Sandstone Fynbos, Cederberg Sandstone Fynbos, Kogelberg Sandstone Fynbos
Description
Peaty margins of seasonal streams, 450-1400 m.
Threats
This species has declined in the past due to habitat loss to crop cultivation in lowland river valleys, as well as dam construction. Subpopulations in montane areas remain vulnerable to further dam construction, which leads to flooding of this species' streamside habitat. Subpopulations are also potentially threatened by competition from alien invasive plants, which tend to spread along drainage lines.
Population

Disa longifolia is a rare, seldom recorded and poorly known species (Liltved and Johnson, unpubl., Linder 1981). It flowers only in the first year after fire, and dormant subpopulations may be overlooked. This species is known from only seven localities, and was recorded only three times in the past 30 years. One of these subpopulations, which consisted of around 200 mature individuals, was subsequently lost to dam construction. The other two occur within protected montane areas, and is not suspected to be declining. A number of historical records indicate that this species formerly occurred in lowland valleys such as the Hex River Valley, Olifants River Valley in the Agter-Witsenberg area, and Riviersonderend Valley near Grabouw, where the species is now locally extinct due to habitat loss. Remaining subpopulations occur in montane areas, where they are not severely threatened.


Population trend
Stable
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Disa longifolia Lindl.VU D2Raimondo et al. (2009)
Disa longifolia Lindl.Lower Risk - Near Threatened Victor (2002)
Disa longifolia Lindl.Rare Hilton-Taylor (1996)
Disa longifolia Lindl.Rare Hall et al. (1980)
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.


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.


Liltved, W.R. and Johnson, S.D. Unpublished. The Cape Orchids - Wild orchids of the Cape Floral Kingdom.


Linder, H.P. 1981. Taxonomic studies in the Disinae. III. A revision of Disa Berg. excluding sect. Micranthae Lindl. Contributions from the Bolus Herbarium 9:1-370.


Linder, H.P. and Kurzweil, H. 1999. Orchids of southern Africa. A.A. Balkema, Rotterdam.


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.


Citation
von Staden, L. 2012. Disa longifolia Lindl. National Assessment: Red List of South African Plants version . Accessed on 2025/04/14

Comment on this assessment Comment on this assessment
Distribution map


Search for images of Disa longifolia on iNaturalist