Watch this space! This is one of the pages written in the prototype stage of this web site, which has been transferred with some additions and alterations to the newer format. It is nevertheless still "under construction", but contains the essential linguistic and botanical information, along with some other material. Updated text and possibly more pictures will be added progressively as soon as time permits (new pages for plant names not yet discussed are being given priority). If you would like this page to be updated sooner than planned, please email a note to temaarareo at gmail.com.
 There are two species of Tetragonia native to Aotearoa, both known as Kōkihi. T. tetrgonioides (illustrated on the left) is commonly referred to a "New Zealand spinach", but it is also native to other parts of the Pacific, including tropical Polynesia, Australia, Japan and southern South America. This is the commercially marketed variety, and has much shorter stems (up to about 60 cm, compared with around 3 metres long for the other species) and slightly larger leaves than the "beach spinach", T. trigyna, which also has reddish (rather than green) stems, and a succulent round red fruit (the fruit of T. tetragonioides is rather woody and is complete with little horns). The natural habitat of T. tetragonioides is along the seashore, on beaches, over driftwood, in rocky places and cliff faces. However it is also found as an escape from cultivation in many other places, including landfills. T. trigyna is native to Aotearoa whānui, and Norfolk and Lord Howe Islands. It is found naturally in a greater variety of marine environments than T. tetragonioides, including coastal forests and shrublands, cliffs and rocky outcrops. Occasionally it may occur on rocky outcrops in forests far inland.
Tetragonia tetragonioides is grown commercially as it is a nutritious vegetable, best cooked as the raw leaves are very mildly poisonous; it also contains oxalic acid so should not be eaten in huge quantities (especially by people prone to gout)! The shoots are rich in saponin, a bitter-tasting glycoside which is used in soap-making and some medicines. According to Murdoch Riley (Herbal, p. 221) the bitterness that develops in older leaves was traditionally removed by boiling the kōkihi with the roots of the pōhue (a kind of convolvulus, used as a food in times of want). The newer leaves are therefore the best to eat. They contain a variety of minerals, including calcium, phosphorus, iron, sodium and potassium, as well as vitamins A, B1, B2 and C. However, remember the oxalic acid! The other species of kōkihi has similar nutritive properties but is perhaps slightly less appetising.
The name is derived from a Proto-Polynesian root denoting primarily a cosmopolitan species of Oxalis; the particular form it takes in Māori is shared with the cognate word in Rarotongan. The alternative Māori name, rengarenga, is a slight mystery, but probably relates to its status as a food eaten occasionally but which came into its own in emergencies. There is no evidence that it was a regular feature in the traditional Māori diet, but James Cook and Jean-François de Surville used it as a remedy for scurvy in their crews in 1769. According to Herries Beattie (Murihiku Notes, n.d., quoted by Riley) the juice was the source of a red ink for nineteenth-century Māori school children to use "to rule their school lessons".
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