Lepidium crassum
Common name
thick-leaved 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 | Threatened – Nationally Endangered | Qualifiers: CD, DP, EF, RR
Previous conservation status
2012 | Threatened – Nationally Endangered | Qualifiers: CD, DP, EF, RR
Brief description
Perennial, strongly aromatic (smelling of cress) herb arising from stout tap-root. Plants with numerous, densely packed leafy branches. Leaves dark green, margins finely serrated , often doubly so. Inflorescences at branch tips, Flowers white with four stamens. Fruits circular, apices rounded or slightly notched, splitting cleanly into two valves, seeds brown or orange-brown.
Distribution
Endemic. New Zealand (South Island - historically upper Waitaki, otherwise easterly from Oamaru south to Otago Peninsula)
Habitat
Coastal headlands and rocky outcrops where it grows in disturbed open areas and among coastal herbfield. Also recorded from man made structures such as the Mole at Aramoana.
Detailed description
Tap-rooted, strongly pungent smelling, perennial herb. Growth habit dense, stems closely placed, up to 0.5m tall, arising from underground woody stems. Stems upright to spreading, stout, short, rigid; mature stems woody, 100–400 × 10–12 mm, often devoid of foliage on middle and lower parts of stems, new stems 50–200 × 4–5 mm, leafy, glabrous. Leaves glabrous, coriaceous, green, undulate, rosette and stem leaves usually withering, variable in size and shape. Leaves of young and vigorous plants and stems: lamina 50–90 × 17–35 mm, broadly elliptic, elliptic to obovate; apex obtuse to truncate, often with up to 3 or 4 teeth; margin singly or doubly crenate, with 15–32 pairs of teeth; teeth up to 3.5 mm deep, sometimes overlapping, often protruding beyond leaf outline; base cuneate, petiole usually distinct; petiole up to 35.0 × 3.0–6.0 mm, channelled. Leaves of mature plants and cauline stems: lamina 15–45 × 6–15 mm, broadly elliptic, elliptic-obovate to obovate-oblong; apex obtuse to truncate, often with up to 3 or 4 teeth; margin singly crenate in upper half, teeth often protruding from leaf outline, with 5–10 pairs of teeth; teeth up to 1.2 mm deep, not overlapping, often protruding beyond leaf outline; base cuneate, sometimes narrowly so, usually tapering to ± distinct petiole; petiole 5–12 × 1.6–2.3 mm, channelled. Inflorescence terminal and lateral, racemose, 15–60 mm long, rachis 0.7–1.2 mm diameter, glabrous; pedicels 4–7 mm long, erecto-patent, glabrous. Flowers 4.0–5.0 mm diameter. Sepals 4, 1.3–1.6 mm long, saccate, overlapping at base, green, apex obtuse, margin white, shape dimorphic; lateral sepals broad, 1.4–1.5 mm diameter, orbicular, abaxial surface often hairy, hairs 0.2–0.5 mm long; median sepals narrow, 1.0–1.3 mm diameter, broadly elliptic, glabrous. Petals white, 1.8–2.0 × 1.0–1.1 mm, spreading, claw 0.6–0.8 mm long; limb broadly elliptic to orbicular, apex obtuse to rounded. Stamens 4; filaments 1.2–1.6 mm long, base 0.4–0.5 mm diameter, equal; anthers 0.4–0.6 mm long. Ovary 1.0–1.6 × 0.9–1.1 mm, broadly ovate to broadly elliptic, green to green-brown, apex round or sometimes weakly shouldered; style 0.15–0.3 mm long, cylindrical; stigma 0.2–0.4 mm diameter. Nectaries 4, 0.2–0.3 × 0.1–0.15 mm, oblong to oblong-triangular, green. Silicles cartilaginous when fresh, coriaceous when dry, 3.0–3.7 × 2.6–3.1 mm, orbicular to orbicular-rhomboid, apex obtuse to shallowly notched, valves pale brown, glabrous, not winged; style 0.2–0.3 mm long, exserted. Seeds 1.6–1.7 × 0.9–1.1 mm, narrowly ovoid, brown to orange-brown, not winged.
Similar taxa
Lepidium crassum differs from the related L. oleraceum by its usually much smaller stature and seasonal growth habit (with plants dying back to a basal rosette overwinter). Lepidium crassum has distinctly petiolate, uniformly broadly elliptic, elliptic to obovate, thickly coriaceous, often doubly crenate leaves with obtuse to truncate apices. Its silicles are usually orbicular, sometimes orbicular-rhomboid, and with obtuse to shallowly notched apices. DNA sequence data places L. crassum with L. aegrum, L. juvencum and L. seditiosum, a clade sister to L. oleraceum (see de Lange et al. 2013).
Flowering
December - March
Fruiting
January - July
Propagation technique
Easily grown from fresh seed but often difficult to maintain in cultivation. Susceptible to a wide range of diseases and pests.
Threats
Lepidium crassum is virtually confined to the Otago Peninsula though historically it ranged from the upper Waitaki River and Oamaru south to the Catlins Coast. It is estimated that there are less than 1000 plants left in the wild, of which thelargest population numbers about 300 plants (see de Lange et al. 2013). The few remaining populations are extremely vulnerable to stochastic events.
Etymology
lepidium: Scale-shaped (pods)
crassum: Thick
Attribution
P.J. de Lange (20 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 crassum Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/lepidium-crassum/ (Date website was queried)