Oxalis thompsoniae
Common names
Thompson’s oxalis
Biostatus
Native
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2023 | At Risk – Naturally Uncommon | Qualifiers: Sp, DPS, DPT, SO
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Flower colours
Yellow
Detailed description
Herb with prostrate or decumbent stems to 450 mm, glabrescent to moderately antrorse-hairy, sometimes with patent septate hairs present; tap root poorly developed; bulbils absent. Leaves cauline, 3-foliolate; leaflets subsessile, cuneate-obovate, 3-16 x 5-20 mm, bilobed, glaucous, glabrous to pubescent above, often densely hairy below, margins ciliate, sinus to 1/3 leaflet length, lobes oblong to slightly obovate, apices rounded, 3-10 mm apart; petioles 40-900 mm long, with simple antrorse hairs; stipules conspicuous, 1-3 mm long, apex rounded, ciliate. Inflorescences axillary 1-6-flowered; peduncles mostly shorter than leaves, sparsely antrorse-hairy; pedicels delfexed in fruit. Sepals oblong, 2-4 mm long, often ciliate; petals 4-12 mm long, yellow. Capsule cylindric, 5-16 mm long, erect, densely covered in retrorse-hairs interspersed with sparse, longer, patent septate hairs; seeds very compressed, smooth or shallowly ribbed.
Similar taxa
Distinguished from Oxalis corniculata by the copious antrorse rather than retrorse stem and petiole hairs, smaller rounded, obtuse tipped, rather than very large, bluntly truncate stipules, which are evenly covered in hairs with the margins distinctly hairer, rather than glabrescent to evenly hairy. The leaves are copiously but finely hairy on both surfaces rather than hairy above glabrous beneath and usually glaucescent, rather than green, dark green, red-green or purple. The seeds of O. corniculata are distinctly ribbed, those of O. thompsoniae are not.
Distribution
Indigenous: Kermadec (Raoul, Macauley), North, South and Chatham (Rekohu only) Islands. Also Australia and New Guinea.
Habitat
Coastal to montane, in grassland, coastal shrub, grey scrub, open sites in forest, on cliff faces and associated rubble slopes. Occasionally in lawns and waste ground in urban situations.
Detailed taxonomy
Genus
Family
Synonyms
None
Endemic taxon
No
Endemic genus
No
Endemic family
No
Ecology
Flowering
September - June
Fruiting
July - June
Propagation technique
Like many Oxalis species, inclined to be weedy in cultivation. This species is locally a problem in some parts of New Zealand but is rarely as weedy as the closely allied O. corniculata.
Other information
Etymology
oxalis: From the Greek word oxus meaning acid or sharp
Chromosome number
2n = 24
Previous conservation statuses
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2017 | At Risk – Naturally Uncommon | Qualifiers: DP, SO, Sp
2012 | At Risk – Naturally Uncommon | Qualifiers: SO, Sp
2009 | Not Threatened
2004 | Not Threatened
Regional conservation statuses
Auckland: 2025 | Regionally Threatened – Regionally Endangered | Qualifiers: Sp, DPR, DPS, DPT, PF, SO
The regional threat classification system leverages off the national assessments in the NZTCS, providing information relevant for the regional context. Auckland conservation status information is sourced from the “Conservation status of vascular plant species in Tāmaki Makaurau / Auckland” Simpkins E et al. (2025) report.
Referencing and citations
Attribution
Fact sheet srepared for NZPCN by P.J. de Lange (10 August 2009). Description from herbarium specimens and live plants.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Oxalis thompsoniae Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/oxalis-thompsoniae/ (Date website was queried)