Ixia sarmentosa

Taxonomy
Scientific Name
Ixia sarmentosa Goldblatt & J.C.Manning
Higher Classification
Monocotyledons
Family
IRIDACEAE
Synonyms
Ixia polystachya L. var. lutea in sense of Lewis (1962), not of Ker Gawl. (misapplied name)
National Status
Status and Criteria
Endangered B1ab(i,ii,iii,iv,v)
Assessment Date
2015/06/30
Assessor(s)
L. von Staden
Justification
EOO 3581 km², between seven and 10 isolated, severely fragmented subpopulations continue to decline due to ongoing habitat loss, degradation and competition from unmanaged alien invasive plants.
Distribution
Endemism
South African endemic
Provincial distribution
Western Cape
Range
Porterville to Kleinmond and Hermanus.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Swartland Alluvium Fynbos, Boland Granite Fynbos, Kogelberg Sandstone Fynbos, Agulhas Limestone Fynbos, Lourensford Alluvium Fynbos
Description
Seasonally wet, lowland flats and slopes.
Threats
This species has already lost most of its habitat in the northern parts of its range to agricultural expansion, and only one confirmed, isolated subpopulation remains in this area. Around Stellenbosch it has also lost habitat to crop cultivation as well as timber plantations on the lower slopes of Simonsberg, where one known remaining subpopulation is threatened by competition from spreading, unmanaged invasive pines. Around Somerset West it is known from one subpopulation protected within the Helderberg Nature Reserve, but is also likely to have declined due to urban expansion on the surrounding lower slopes of Helderberg Mountain in the past. On the coast between Betty's Bay and Hermanus, this species continues to be threatened by habitat loss to coastal development, as well as competition from unmanaged alien invasive plants.
Population

This species is rare and poorly known, but may also be overlooked due to taxonomic confusion. Subpopulations are scattered, and isolated due to habitat loss and fragmentation. Population data available for one subpopulation indicate that this species occurs as small, localized groups of individuals. It continues to decline due to ongoing habitat loss and degradation across its range.


Population trend
Decreasing
Notes
This poorly known species is often confused with another yellow-flowered, but more common species, Ixia dubia, and the two species co-occur in places. Specimen collections are essential to differentiate the species.
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Ixia sp. nov. (Goldblatt & Manning 13747 NBG)EN B1ab(i,ii,iii,iv,v)2015.1
Ixia polystachya L. var. lutea (Ker Gawl.) G.J.LewisLeast Concern Raimondo et al. (2009)
Bibliography

Goldblatt, P. and Manning, J.C. 2016. Systematics of the southern African genus Ixia L. (Iridaceae): 5. Synopsis of section Ixia, including five new species. South African Journal of Botany 104:175-198.


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
von Staden, L. 2015. Ixia sarmentosa Goldblatt & J.C.Manning. National Assessment: Red List of South African Plants version 2017.1. Accessed on 2017/12/14

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Distribution map

© A.G. Rebelo

© A.G. Rebelo


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