Species

Lepidium obtusatum

Etymology

Lepidium: scale-shaped (pods)
obtusatum: Obtuse, or blunt

Current Conservation Status

2012 - Extinct

Conservation status of New Zealand indigenous vascular plants, 2012
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2012 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2009 and replaces all previous NZTCS lists for vascular plants. Authors: Peter J. de Lange, Jeremy R. Rolfe, Paul D. Champion, Shannel P. Courtney, Peter B. Heenan, John W. Barkla, Ewen K. Cameron, David A. Norton and Rodney A. Hitchmough. File size: 792KB

Previous Conservation Status

2009 - Extinct
2004 - Extinct

Authority

Lepidium obtusatum Kirk

Family

Brassicaceae

Flora Category

Vascular - Native

Structural Class

Dicotyledonous Herbs other than Composites

Synonyms

None

Distribution

Endemic. North Island, Waitakere Coastline (between Karekare and the Manuaku Heads), and Wellington (Seatoun to Fort Dorset). Not seen since 1917 (northern population) and 1950 (southern population on the Miramar peninsula in Wellington) and now presumed extinct. Not known in cultivation. First collected in the Wellington area prior to 1892 and near the Manukau Heads in 1870.

Habitat

The Manukau specimens are furnished with scant information. It would appear that these where collected from cliff faces. The Wellington plants grew mainly in fine beach gravel and stable talus slopes between Seatoun and Point Dorset. At this site it may also have grown on cliff faces.

Features

Glabrous decumbent to semi-erect herb forming circular patches up to 300 mm diam. Stems stout, fleshy, somewhat flexuous. Rosette and basal leaf petioles, broad, flat up to 80 mm long. Lamina 30-70 x 5-20 mm, fleshy, succulent, oblong-cuneate, obovate, coarsely crenate-serrate, dark green. Cauline leaves subsessile to sessile, lamina (5-)10-20(-50) x (3-) 5(-15) mm, fleshy-succulent, obovate, ovate to broadly ovate, crenate, rarely toothed, dark green. Inflorescence a terminal raceme (20-)3(-50) mm long, these numerous. Flowers 3-4 mm diam.; pedicels 3-5 mm, erecto-patent sometimes decurved; sepals broadly ovate-oblong, c.1.5. mm long; petals white, obovate < or = to sepals. Stamens 4(-6). Silicle 4.5-5.5 x 4-4.5 mm, broadly ovate, shallowly notched at apex, slightly winged; style very short; stigma = notch. Seeds broadly ovoid to triangular, orange brown, 2 x 2 mm.

Similar Taxa

Traditionally allied to the Lepidium banksii Kirk, from which it is easily distinguished by the decumbent to suberect growth habit, obovate, oblong-crenate leaves, very long petiolate rosette leaves, and glabrous pedicels. Recently obtained (2005) nrDNA ITS/ETS sequences suggest that although nested within the L. oleraceum group of Lepidia it was not closely allied to either L. banksii or L. oleraceum s.s.

Flowering

December - July

Flower Colours

White

Fruiting

December - July

Propagation Technique

Not Applicable. However, seed obtained from a 1938/39 (exact year of collection not clear) and sown in 1993 took up water and began to germinate but then died. Possibly this experiment should be repeated but as an extinct species, seed is obviously limited.

Threats

The Wellington population seems to have been eliminated through a combination of habitat destruction and over collection by people. It is not clear why this species disappeared from the Waitakere Coastline.

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

Life Cycle and Dispersal

Mucilaginous seeds are dispersed by attachment and possibly wind and water (Thorsen et al., 2009).

Where To Buy

Extinct plant so unavailable.

Notes on its status

Only one account of this species appearance when alive is known, and that suggests it was a very fleshy, succulent herb with dark green leaves. Specimens from the Manukau Harbour differ from Wellington plants by their much more coarsely toothed rosette leaves and semi-erect to erect rather than creeping habitat. The Wellington population appears to have alway been of rather restricted occurrence and its loss seems to have been due to a combination of excessive plant collection by botanists, weed invasion and destruction of the main population as a consequence of gravel extraction. There have been numerous surveys for this species in the Wellington area but the Manukau (Waitakere Heads) have hardly been surveyed. Indications are that it was already very uncommon in that area when it was discovered.

Attribution

Fact Sheet by P.J. de Lange: Description adapted from de Lange et al. (2013).

References and further reading

de Lange, P.J. 2005. A final word from Lepidium obtusatum? Wellington Botanical Society Bulletin, 49: 7-8.

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.

Thorsen, M. J.; Dickinson, K. J. M.; Seddon, P. J. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 11: 285-309

This page last updated on 3 Jun 2015