Lepidium seditiosum
Common name
Bounty Islands scurvy grass
Synonyms
None (first described in 2013)
Family
Brassicaceae
Flora category
Vascular – Native
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Structural class
Herbs - Dicotyledons other than Composites
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.
LEPSED
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2017 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants.
Please note, threat classifications are often suggested by authors when publications fall between NZTCS assessment periods – an interim threat classification status has not been assessed by the NZTCS panel.
- Conservation status of New Zealand indigenous vascular plants, 2017 . 2018. Peter J. de Lange, Jeremy R. Rolfe, John W. Barkla, Shannel P. Courtney, Paul D. Champion, Leon R. Perrie, Sarah M. Beadel, Kerry A. Ford, Ilse Breitwieser, Ines Schönberger, Rowan Hindmarsh-Walls, Peter B. Heenan and Kate Ladley. Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2017 | Threatened – Nationally Critical | Qualifiers: CD, DP, EF, IE, OL
Previous conservation status
2012 | Threatened – Nationally Critical | Qualifiers: CD, DP, IE, OL
Brief description
Dark green, leafy herbaceous plant. Leaves with jagged margins, aromatic (smelling of watercress when crushed). Flowers in leafy terminal inflorescences, white. As with all other N.Z. Lepidium species the fruits are flattened, 2-valved capsules, these shed at maturing. Mature fruits and seeds for this species have yet to be seen.
Distribution
Endemic. Bounty Islands (Funnel and Molly Cap Islands). Lepidium seditiosum is the only flowering plant known to occur on the Bounty Islands (see Amey et al. 2007).
Habitat
Rock ledges and crevices
Detailed description
Erect, perennial herb. Stems sparse, erect; mature stems long, 4.14–4.41 mm diameter stout, woody, rigid, ± square, prominently angled, bases much covered in leaf abscission scars, middle and upper portion leafy. Leaves fleshy, dark green, stem leaves evidently withering with age; petiole distinct, 14–22.0 × 1.9–2.6 mm, decurrent, prominently channelled, broadly winged, with a broadly sheathing base; lamina variable 32.4–45.4 × 21.2–26.4 mm decreasing in size toward inflorescences, broadly elliptic, elliptic to oblanceolate; apex praemorse or tridentate; margin coarsely and ± regularly dentate to deeply incised; teeth protruding beyond leaf outline; in 8–12 uneven pairs, up to 5.3 mm deep, increasing in size toward apex; base broadly attenuate tapering, extending into a broad petiole wing. Inflorescences immature but evidently racemose, rachis 1.3–1.5 mm diameter, terminal and lateral, leaf-opposed, densely and mostly circumferentially covered in 0.4–0.6 mm long, white, clavate hairs; pedicels 1.6–2.2 mm long at flowering, erecto- patent, densely and mostly circumferentially covered in 0.4–0.6 mm long, white, clavate hairs. Flowers 2.3–2.6 mm diameter. Sepals 4, saccate, dark green usually with a narrow white, ± undulose margin; lateral sepals broad, 0.8–1.2 mm diam., obovate to broadly obovate, ± overlapping at base, apex rounded to obtuse, abaxial surface densely hairy, hairs 0.1–0.4 mm long, eglandular or glandular, mostly clavate, some setose, median sepals 0.8–1.0 mm diam., broadly obovate, dark green, usually with a narrow white, ± undulose margin, apex rounded to obtuse, abaxial surface densely hairy, hairs 0.1–0.4 mm long, eglandular or glandular, mostly clavate, some setose. Petals white, 1.3–2.0 × 1.0–2.3 mm, mostly recurved over stigma some spreading, claw 0.4–0.9 mm long; limb obovate, obovate-spathulate rarely orbicular, apex obtuse or slightly emarginate, margins smooth. Stamens 4, filaments 1.2–1.8 mm long, white; anthers 0.3–0.4 mm long, yellow. Ovary 1.1–1.8 × 0.6–1.3 mm, broadly ovate to elliptic, dark green, apex round or weakly notched; style 0.11–0.4 mm long, cylindrical below, broadly spreading at apex; stigma 0.2–0.4 mm diameter. Nectaries 4, 0.2–0.3 × 0.1–0.15 mm, narrow-oblong, pale translucent green. Mature silicles not seen.
Similar taxa
Morphologically, Lepidium seditiosum is most similar to the Chatham Islands endemic Lepidium panniforme, which also has deeply toothed (though also lacerate leaves) but whose stems and inflorescence rachis are glabrous (only very rarely furnished with sparse silky hairs). However, Lepidium seditiosum differs from L. panniforme (and indeed all other members of the Lepidium oleraceum complex) by its distinctly clavate-hairy upper stems and inflorescence rachises. DNA sequence data clearly places L. seditiosum with the Southern island endemics L. aegrum, L. crassum and L. juvencum from which it is easily separated by its deeply toothed leaves, and hairy inflorescences. Although mature silicles are as yet unknown from L. seditiosum (which is only known from the holotype), the immature fruits suggest that in this species the apices are deeply notched.
Flowering
November
Flower colours
White
Fruiting
Mature fruit not seen
Life cycle
Probably a short-lived perennial. Seed almost certainly dispersed by sea birds as well as by water and gravity.
Propagation technique
Unknown - probably has the same cultivation requirements as Lepidium oleraceum (see that species fact sheet)
Threats
Lepidium seditiosum was discovered in November 2004 (see Amey et al. 2007). When it was discovered ‘at least 13’ plants were recorded from two sites (Funnel Island (12 plants) and Molly Cap (1 plant). On this basis, L. seditiosum qualifies as ‘Threatened / Nationally Critical’. The species is also appropriately qualified ‘CD’ (Conservation Dependent), ‘DP’ (Data Poor – because accurate data on the total number of individuals and trend data is not available), ‘IE” (Island Endemic), and ‘OL’ (One Location – as the species is confined to the Bounty Islands group). For more details see de Lange et al. (2013).
Etymology
lepidium: Scale-shaped (pods)
seditiosum: The epithet ‘seditiosum’ is derived from the Latin ‘seditio’ (meaning: dissension, insurrection, mutiny, rebellion), and alludes to the mutiny of the majority of Lieutenant William Bligh’s crew on the 28 April 1789. In 1788, some months before the rebellion, Bligh had discovered and named the Bounty Islands (where this species is endemic) taking the name from his ill-fated ship The Bounty (see de Lange et al. 2013).
Attribution
P.J. de Lange (11 August 2013). Description from de Lange et al. (2013) - see references for free download link for that paper.
References and further reading
Amey J, Lord JM, de Lange P (2007) First record of a vascular plant from the Bounty Islands: Lepidium oleraceum (nau, Cook’s scurvy grass) (Brassicaceae). New Zealand Journal of Botany 45: 87–90. doi: 10.1080/00288250709509705
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.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Lepidium seditiosum Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/lepidium-seditiosum/ (Date website was queried)