Lepidium amissum
Common name
Waitakere 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
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 | Extinct
Previous conservation status
2012 | Extinct
Brief description
Perennial herb arising from stout tap-root. Plants with untidy, suberect to sprawling, leafy branches. Leaves dark green, with deeply toothed margins (probably smelling of cress when crushed). Inflorescences at branch tips, Flowers white with four stamens. Fruits circular, apices deeply notched, splitting cleanly into two valves, seeds orange-brown or brown.
Distribution
Endemic. New Zealand. North Island (Waitakere Ranges Coastline)
Habitat
Coastal cliffs. Exact habitat preferences unknown (see de Lange et al. 2013)
Detailed description
Glabrous, suberect, sparingly branched, succulent, perennial, herb forming open patches up to c. 1 m diameter. Rootstock stout, woody, exposed portion rough, covered in old dead stem and rosette-leaf remnants admixed with actively growing stems. Stems arching, widely spreading, possibly with apices weakly ascendent, succulent, mature stems woody, 200–300 × 3–6 mm, densely leafy near base, leaves more widely spaced along upper stems. Leaves glabrous, coriaceous, probably succulent, dark green, planar, variable size and shape. Rosette leaves persistent at fruiting 71.7–95.2 × 12.4–23.2 mm, spathulate; apex, truncate, praemorse, with 3–8 deeply incised teeth; margin coarsely and often irregularly incised or dentate, often weakly bidentate, with 24–36 pairs of teeth; teeth up to 4.8 mm deep, irregular in size, protruding beyond leaf outline; base narrowly attenuate to cuneate, ± decurrent, petiole distinct, 43.4–55.2 × 1.4–2.3 mm long, slightly winged, or not, channelled. Lower stem leaves similar to rosette leaves, apparently persistent, widely spaced, gradually decreasing in size toward inflorescence; petioles distinct, slightly winged or not. Upper stem leaves much reduced; lamina 10.3–27.5 × 3.4–7.6 mm, lanceolate, narrowly oblanceolate, lanceolate to narrowly oblanceolate-spathulate to obovate obdeltoid, apex truncate, with 3–4 prominent teeth, margins prominently toothed in upper third of lamina with 4–6 deeply incised pairs of teeth (rarely entire except for apex), base cuneate to broadly cuneate; petiole distinct or indistinct, up to 6 mm long when present, channelled. Inflorescence racemose, terminal and lateral, conspicuous, sparingly leafy and unfettered by associated vegetative leafy stems; racemes 22–68 mm long, rachis 0.9–1.6 mm diam., glabrous; pedicels 2.8–3.2 mm long at flowering, erecto- patent, elongating somewhat after anthesis, glabrous. Flowers 4.3–4.6 mm diameter. Sepals 4, saccate, overlapping at base, green, apex obtuse, margin white, shape and size dimorphic; lateral sepals 2.2–2.9 × 2.1–3.0 mm, suborbicular, mostly glabrous, sometimes sparsely hairy, hairs 0.2–0.4 mm long, caducous; median sepals 1.9–2.9 × 1.5–1.7 mm, broadly elliptic to obovate, abaxial surface glabrescent, sparsely hairy, hairs 0.2–0.4 mm long, caducous. Petals white, 1.3–1.8 × 1.3–1.8 mm, erect, claw minute, 0.2–0.3 mm; limb orbicular, apex obtuse. Stamens 4, ± equal lengths, 1.2–1.8 mm long, base 0.6–1.0 mm wide; anthers 0.6–0.8 mm long, yellow, pollen yellow. Ovary 1.3–1.8 × 1.3–1.7 mm, broadly ovate to suborbicular green, apex distinctly notched; style 0.3–0.5 mm long, cylindrical below, spreading at apex; stigma 0.5–0.6 mm diameter. Nectaries 4, green, 0.12–0.14 × c. 0.09 mm, narrow oblong, apex obtuse. Silicles 3.4–4.5 × 2.9–3.9 mm, broadly ovate, oval to obovate, apex prominently notched, valves yellow-green (in dried specimens), glabrous, slightly winged; style 0.2–0.5 mm long, not or only slightly exserted. Seeds 2.0–2.7 × 1.8–2.0 mm, obovate, broadly obovate, brown to orange-brown, not winged.
Similar taxa
Lepidium amissum was previously included within another extinct species Lepidium obtusatum. From that species L. amissum differs by the non-rhizomatous, suberect growth habit; arching, sparingly leafy stems; long persistent, deeply, and sharply incised rosette and lower stem leaves; upper stem leaves which are lanceolate, narrowly oblanceolate, to narrowly obdeltoid and mostly prominently toothed, with up to 6 pairs of deeply incised teeth, and with a truncate apex bearing 3–4 prominent teeth. The inflorescences of L. amissum are larger, only sparsely leafy when mature, and without associated vegetative stems. The silicles are smaller than those of L. obtusatum.
Flowering
December - January
Fruiting
December - January
Propagation technique
Unknown. Species is extinct.
Threats
Extinct. The reasons for the extinction of Lepidium amissum are not clear. The species is known only from four herbarium sheets, one of these collected in 1870 and the other three portions of the same gathering made in 1917. The species was evidently already very uncommon when it was “discovered” by Thomas Cheeseman, who it seems unwittingly contributed to its extinction. Much of the coastline from where this species was said to grow was grossly modified during the late 1800s and early 1900s and this may have contributed to this species demise.
Etymology
lepidium: Scale-shaped (pods)
amissum: From amissus - meaning missing, in reference to the loss through extinction of this species from our indigenous flora (see de Lange et al. 2013)
Attribution
P.J. de Lange (15 August 2013). Description from de Lange et al. (2013) - see references for free download link for that paper.
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.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Lepidium amissum Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/lepidium-amissum/ (Date website was queried)