Lepidium oligodontum
Common names
scurvy grass
Biostatus
Native – Endemic taxon
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 – Relict | Qualifiers: CD, EF, RR
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Simplified description
Flat, sprawling summer-green perennial herb forming circular patches on substrates. Plants dying down to rootstock and/or previous seasons stem nodes. Rosette leaves narrowly spathulate, cuneiform, obdeltoid, obovate or rarely elliptic-lanceolate; these mostly present in autumn – early spring often persisting once flowering has ceased. Upper stem leaves narrowly cuneiform, oblanceolate, or narrowly obdeltoid, apically toothed, often sparingly or entire. Flowers with four white petals and 2-6 stamens, with four being the usual number. Fruit a silicle, these fleshy and distinctly turgid when fresh, broadly orbicular to orbicular with a faint winged margin, apex not or very slightly notched.
Flower colours
White
Detailed description
Tap-rooted, decumbent, rather flaccid, pungent-smelling, summer-green, succulent, perennial herb forming sparse to densely leafy, circular ± flat masses up to 1 m diam., and arising from stout, semi-circular, greyish-white or reddish-grey (when exposed) rootstock 6.0–30.0 mm diam. Tap root woody, up to 0.2 m long, deeply descending. Plants dying down to rootstock and/or previous seasons stem nodes, at fruit set or soon thereafter. Stems decumbent, widely spreading, up to 0.8 m long and 3.20–4.56(–5.20) mm diam., ± woody throughout, ± square to somewhat angular-spheroidal in cross-section and prominently ridged on angles (this especially conspicuous when dry), dark reddish-green to dark green when fresh, drying dull grey; stems usually heavily branched from base, branches and branchlets numerous, prostrate, widely spreading, and usually very leafy; basal portion of stems, glabrous. Leaves glabrous, succulent, dark green, green to yellow-green at senescence turning yellow. Rosette leaves 5–10(–14), mostly present in autumn – early spring but not persisting (very rarely so) at fruiting; petioles distinct up to 70 × 2 mm, flat or slightly concave in cross-section, succulent; lamina narrowly spathulate, cuneiform, obdeltoid, obovate or rarely elliptic-lanceolate, up to 60 × 22 mm, margins entire, or sparingly dentate in upper ⅓, if teeth present then in 1–3(–5) pairs running to and including the usually tridentate apex, basal teeth often asymmetric, base narrowly cuneate, cuneate to attenuate. Middle stem leaves persistent or not at fruiting; petiole usually distinct (rarely not) up to 14.0 × 1.13 mm, mostly flat in cross-section, sometimes slightly concave, succulent; lamina spathulate, cuneiform, linear-cuneiform, oblanceolate, narrowly ovate, to narrowly obovate, or rarely orbicular, 10.6–22.8(–33.2) × 5.4–9.2(–17.5) mm; margins entire, or sparingly dentate with 1–2–3(–5) pairs of teeth in upper ⅓ apex usually tridentate, basal teeth often asymmetric, lamina base narrowly attenuate, attenuate, cuneate or rarely acute. Upper stem leaves usually without a distinct petiole, petiole if present 1.0–3.6 mm, flat or slightly concave; lamina narrowly cuneiform, oblanceolate, or narrowly obdeltoid, 7.6–10.8(–11.9) × 2.7–3.1(–3.5) mm; margins entire or weakly dentate to deeply incised, if dentate or incised then with 1(–2) often asymmetrical teeth present in the upper ⅓, apex entire or tridentate, lamina base cuneate to narrowly cuneate. Racemes (5.0)–9.7(–28.9) mm long, usually congested, elongating up to 60 mm at fruiting, terminal and axillary; rachis and pedicels glabrous; pedicels, erecto-patent to patent,0.82–1.00(–2.08) mm, 2.1–3.5(–6.1) mm long at fruiting. Flower buds dark green to green, apex glabrous. Flowers sweetly fragrant, 1.2–1.5(–2.2) mm diam. Sepals 4, saccate, pale to dark green with a broad white, ± undulose margin, pale to dark green with a broad white, ± undulose margin, deeply concave, adaxially weakly keeled or not; lateral sepals 0.9–1.4 × 0.8–1.2 mm, broadly ovate to oblong, ± overlapping at base, apex rounded to obtuse, adaxial surface mostly glabrous sometimes diffusely papillate, abaxial surface often hairy, hairs patent, weakly flexuous, 0.1–0.4 mm long, eglandular, mostly shedding at anthesis except near base; median sepals 1.0–1.4 × 0.9–1.2 mm, broadly ovate to oblong, apex rounded to obtuse, adaxial surface glabrous, abaxial surface usually glabrous, rarely sporting a small tuft of patent, eglandular, flexuous hairs 0.1–0.2 mm long. Petals usually present (occasionally absent) usually equal to or slightly overtopping sepals (rarely > sepals), white, 0.8–1.6(–1.9) × 0.6–1.2(–1.8) mm, patent, clawed; limb broadly obovate, apex obtuse, rarely retuse. Stamens 2–4(–6), equal. Anthers c.0.14 mm long. Pollen bright yellow. Nectaries 2, subulate, 0.32 mm long. Silicles somewhat fleshy and distinctly turgid when fresh, on drying collapsing to form a coarse reticulum, broadly orbicular to orbicular, (3.0)–3.5(–3.8) × (2.8–)3.0–3.2(–3.8), margin slightly winged, sometimes more so toward apex, apex not or very slightly notched, base cordate (rarely truncate), valves green maturing yellow-green, glabrous; style 0.2–0.8(1.2) mm long, free from the narrow wing, equal to or slightly exceeding the notch; stigma 0.4–0.6 mm diam. Seeds 2, ovoid to suborbicular, light red-brown or red-brown, not winged, 0.84–0.98 × 0.80–1.00 mm.
Similar taxa
Lepidium oligodontum is recognised by the combination of having a decumbent rather than erect growth habit, glabrous stems, branchlets and pedicels, leaves which are either sparingly toothed or entire, flowers with 2–4(–6) stamens, and silicles mostly broadly orbicular to orbicular, slightly winged, mostly cordate-based, and that are distinctly swollen (turgid) when fresh and whose apices are slightly notched.
Distribution
Endemic. New Zealand, Chatham and Antipodes islands. On the Chatham Islands, it is known from Rekohu | Wharekauri | Chatham Island and Hokorereoro | Rangatira | South West Islands, and from all of the outlying islets and vegetated rock stacks except Maung’Re | Mangere, Tapuaenuku | Little Mangere and the Motchu’char | Motuhara | Forty-fours. It is apparently absent from Rangahaute | Rangiauria | Pitt Island. On the Antipodes it is only known from Antipode Island, that largest island in the group.
Habitat
Lepidium oligodontum is a strictly coastal, island endemic inhabiting richly manured, frequently disturbed habitats, and it is an important component of the distinctive guano-dependent vegetation that has developed in the presence of New Zealand fur seals (Arctocephalus forsteri) and sea birds. It has been observed that Lepidium oligodontum soon vanishes if seals and seabirds are excluded from its habitats. Lepidium oligodontum has a very seasonal growth pattern, with most vegetative growth occurring from late winter to summer after which plants are scarcely visible during autumn and early winter. During this time growth virtually ceases and most of the foliage, branches, branchlets and inflorescences wither away. While ‘dormant’, plants persist as minute leafy shoots clustered around the rootstock apex, or as a single leafy rosette so are very easily overlooked.
Threats
Of all the Lepidium oleraceum complex L. oligodontum seems to have the closest relationship with sea mammals and birds. In habitats frequented by these animals it is often common. In places where they have vanished from it soon goes extinct. Past attempts at restoring plants into the wild in places where these animals are absent have all failed. Current management therefore has focussed on ensuring the remaining populations of Lepidium on island systems with intact sea mammal / bird dominated ecosystems remain that way with biosecurity a key focus. Lepidium oligodontum is also extremely susceptible to Albugo lepidii, an oomycete which has been found in all known populations, and which will kill plants in cultivation. In the wild Albugo outbreaks vary from season to season but in some years are so severe as to kill plants or so severely damage their growth that flowering and seed set is lessened. A genetic study has revealed that Chatham Island species of Albugo lepidii differ slightly from those in New Zealand and elsewhere, suggesting that this disease colonised the Chatham Islands some time ago, and drifted slightly in isolation. Research is needed to see if whether this oomycete indigenous, endemic or naturalized, is truly a critical constraint on the growing season, flowering and fruiting of this species, especially in what appear to be ecologically suboptimal sites.
Detailed taxonomy
Genus
Family
Synonyms
None (first described in 2013)
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Other information
Etymology
lepidium: Scale-shaped (pods)
oligodontum: The epithet ‘oligodontum’ means ‘few teeth’ and refers to the leaves of this species which may be deeply toothed, sparingly toothed near the apex or entire, sometimes with all three conditions on the same plant (see de Lange et al. 2013).
NVS code
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
LEPOLI
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 | Threatened – Nationally Vulnerable | Qualifiers: CD, EF, RR
2012 | Threatened – Nationally Vulnerable | Qualifiers: DP, EF, RR
Referencing and citations
References and further reading
de Lange, P.J.; Heenan, P.B.; Houliston, G.; Rolfe, J.R.; Mitchell, A.D. 2013: New Lepidium (Brassicaceae) from New Zealand. Phytokeys 24:1-147pp. doi: 10.3897/phytokeys.24.4375.
Attribution
Fact Sheet prepared for NZPCN by P.J. de Lange 1 March 2025. Description from de Lange et al. (2013)
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Lepidium oligodontum Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/lepidium-oligodontum/ (Date website was queried)