''Lepidium banksii'', known as coastal peppercress, is a rare species of flowering plant from the family

Brassicaceae Brassicaceae () or (the older but equally valid) Cruciferae () is a medium-sized and economically important Family (biology), family of flowering plants commonly known as the mustards, the crucifers, or the cabbage family. Most are herbaceous pla ...

. It is endemic to New Zealand, formerly found around the coast of the northern

South Island The South Island ( , 'the waters of Pounamu, Greenstone') is the largest of the three major islands of New Zealand by surface area, the others being the smaller but more populous North Island and Stewart Island. It is bordered to the north by ...

but now critically endangered.

Discovery

Coastal peppercress was first collected for culinary purposes: by

Cook Cook or The Cook may refer to: Food preparation * Cooking, the preparation of food * Cook (domestic worker), a household staff member who prepares food * Cook (profession), an individual who prepares food for consumption in the food industry * C ...

, in 1770 in the

Marlborough Sounds The Marlborough Sounds (Māori language, te reo Māori: ''Te Tauihu-o-te-Waka'') are an extensive network of ria, sea-drowned valleys at the northern end of the South Island of New Zealand. The Marlborough Sounds were created by a combination ...

, along with its relative '' Lepidium oleraceum'', as a treatment for

scurvy Scurvy is a deficiency disease (state of malnutrition) resulting from a lack of vitamin C (ascorbic acid). Early symptoms of deficiency include weakness, fatigue, and sore arms and legs. Without treatment, anemia, decreased red blood cells, gum d ...

. Both species are members of the

or cabbage family and contain vitamin C. It was collected again in 1827 by

Dumont d'Urville Jules Sébastien César Dumont d'Urville (; 23 May 1790 – 8 May 1842) was a French explorer and naval officer who explored the south and western Pacific, Australia, New Zealand and Antarctica. As a botanist and cartographer, he gave his name ...

in Queen Charlotte Sound and Astrolabe Harbour (now in

Abel Tasman National Park Abel Tasman National Park is a national park at the north end of New Zealand's South Island. It covers of land between Golden Bay / Mohua and Tasman Bay / Te Tai-o-Aorere, making it the smallest of National parks of New Zealand, New Zealand's ...

), and from those specimens was described by Thomas Kirk in 1899 and named after

Sir Joseph Banks Sir Joseph Banks, 1st Baronet, (19 June 1820) was an English naturalist, botanist, and patron of the natural sciences. Banks made his name on the 1766 natural-history expedition to Newfoundland and Labrador. He took part in Captain James Co ...

, the naturalist on Cook's first voyage.

Description

Coastal peppercress is a low rambling fleshy-leaved coastal herb. It resembles the closely related Cook's scurvy grass or nau (''L. oleraceum''), but is darker in colour and with more deeply toothed leaves. Its seed pods are much larger and deeply notched, and it each winter it dies back to its rootstock.

Distribution

''Lepidium banksii'' is strictly coastal, growing in boulder banks and on shell banks in estuaries. Formerly it was found in the northern

, from

Karamea Karamea is a town on the West Coast, New Zealand, West Coast of the South Island of New Zealand. It is the northernmost settlement of any real size on the West Coast, and is located northeast by road from Westport, New Zealand, Westport. Apart ...

on the West Coast to Tasman and

Golden Bay Golden Bay may refer to: * Golden Bay / Mohua Golden Bay / Mohua is a large shallow bay in New Zealand's Tasman District, near the northern tip of the South Island. An arm of the Tasman Sea, the bay lies northwest of Tasman Bay / Te Tai-o-Aore ...

s and the

, but by the 1950s had grown so scarce that Allan writing the ''Flora of New Zealand'' series was unable to refer to a recent specimen. In 1988, Phil Garnock-Jones was revising the New Zealand ''Lepidium'' species, and realised that ''L. oleraceum'' specimens collected in 1961 near

Tōtaranui Tōtaranui is a 1 km long beach and the site of a large campsite in the Tasman Region of New Zealand administered by the Department of Conservation (New Zealand), Department of Conservation (DOC). It is located in Abel Tasman National Park ...

were actually ''L. banksii''. Field surveys revealed the plant was still there. It was also discovered in the Waimea Estuary near

Nelson Nelson may refer to: Arts and entertainment * ''Nelson'' (1918 film), a historical film directed by Maurice Elvey * ''Nelson'' (1926 film), a historical film directed by Walter Summers * ''Nelson'' (opera), an opera by Lennox Berkeley to a lib ...

during a survey by

DOC DOC, Doc, doc or DoC may refer to: People and characters * Doc, an abbreviation of doctor * Doc (nickname) * Doc (mascot), the Towson University mascot Persons * The D.O.C., American rapper (born 1968) * Doc Gallows (born 1983), ring nam ...

botanist Shannel Courtney.

Conservation

''Lepidium banksii'' is the rarest of New Zealand's 11 ''Lepidium'' species. By 1991 only 22 plants were known in the wild. In 1994, a new population of about 450 was discovered in a remote cove in Abel Tasman National Park, but soon after these were all destroyed by feral pigs. The species is very vulnerable to pests and diseases, and proved to be extremely difficult to cultivate and successfully replant in the wild. A new strategy of sowing seed directly in guano-rich soils where seabirds congregated proved more fruitful, and by the mid 2000s hundreds of plants were successfully established and self-seeding. ''L. banksii'' was functionally extinct in the wild, and its entire population continues to rely on ongoing artificial propagation efforts.

References

External links

* ''Lepidium banksii'' on RNZ ''Critter of the Week''
20 May 2016
{{Taxonbar, from=Q17240981 Endemic flora of New Zealand Plants described in 1899 banksii Endangered flora of New Zealand Nelson, New Zealand