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Introduction
Species
Toxicity
Beverages: Wai puhou and Tewe
Other Uses: Ecological, Medical and Musical
Tutu in Proverbs and Poetry
Tutu is the superstar of New Zealand's poisonous plants, having accounted for the demise of many cattle, a couple of elephants, a fair few sheep, and a distressing number of children along with a few of their parents, especially in the 19th Century -- fortunately, farmers and the general public are now more aware of its dangers, so human casualties at least, are now virtually unknown. Its tropical namesake, Colubrina asiatica, while having a similar arrangement of the leaves and habit of growth has a very different inflorescence and will not poison people or animals who ingest its leaves, seeds or stems. (Its qualities are discussed on the linked page.)
There are currently seven New Zealand species of the genus Coriaria. Most are lowgrowing shrubs, except for Coriaria arborea; all are known as tutu. C. arborea is found throughout New Zealand, var. arborea in the North, South and Stewart Islands and the Chatham Islands, and var. kermadecensis on the Kermadecs. The plant may be a large rather tangled many-branched shrub, or develop into a round-trunked tree six metres or more high. The twigs and branches of all tutu species are square in cross-section and the leaves emerge in pairs from the stems with either no or extremely short stalks. On C. arborea var arborea the dark-green, glossy, eliptical leaves are 5 - 8 cm long and a little more than half as wide; the Kermadec Island variety has much lighter green foliage, and is badly affected by cold weather. The flowers appear in drooping racemes 30-50 cm long with flower-stalks (pedicels) about 5 mm long (rather shorter in the Kermadec variety). An ancient species, C. latepetiolata, had been described by W.R.B. Oliver on the basis of fossils from near Dunedin; these were later thought by Mike Pole ("Monocot Macrofossils from the Miocene", p.1) to have in fact been the remnants of a species of Ripogonum (kareao); however the original identification in the Te Papa database and collection has since been confirmed.
Species of tutu
Most of this page will be focused on Coriria arborea var arborea, but the notes about its poisonous and other properties generally apply also to the other species. The species do differ in their size, geographical distributions and the concentrations of the neurotoxin tutin in their leaves and stems, as outlined in the notes below. The toxin data is from H.E. Connor's Poisonous Plants, pp. 58-61, and refers to the percentage of tutin detected in samples of leaves and stems, respectively, or in mixed samples – despite the variations all are toxic and should be regarded as potentially deadly.
Coriaria arborea. A large shrub or small tree, with two named varieties: var. arborea, found throughout mainland New Zealand, Stewart Island and the Chatham Islands, and var. kermadecensis, confined to the Kermadec Islands.
Toxicity: leaves 0.05-0.09; stems 0.05-0.08.
(Photo: P. B. Heenan, (c) Landcare Research.)
Coriaria angustissima.
A small shrub with very narrow (1-2 mm wide) pointed leaves about 1 centimetre long, growing in wet upland areas in the South Island and Stewart Island.
Toxicity: leaves 0.19; stems 0.025.
(Arthurs Pass. Photo: John Smith-Dodsworth, (c) NZPCN.)
Coriaria kingina. A low-growing, bushy shrub with dark-green wavy leaves 12-15mm long by 5-10 mm wide, broader at the base and pointed at the top. Found in the upper North Island, often associated with rau-aruhe.
Toxicity: not stated.
(Kuripango, Kaweka Ranges. Photo: (c) Jeremy Rolfe, NZPCN.)
Coriaria plumosa. A low-growing bush with small, narrow dark-green leaves 6-8 mm long, and 1.5-3 mm long (widest at the base). Found in open montane environments in the lower half of the North Island and the South Island.
Toxicity: mixed sample, 0.05-0.65.
(Photo: John Smith-Dodsworth, (c) NZPCN.)
Coriaria pottsiana. This is the only New Zealand species of Coriaria that is rare and potentially endangered. It is a low-growing shrub with small, wavy bronze leaves 6-8 mm long by 5-6 mm wide, widest in the middle. It is found on Mounts Hikurangi and Parikanapa on the North Island East Coast. Toxicity not stated.
(Gisborne. Photo: (c) Mike Thorsen, NZPCN.)
 Coriaria pteridioides. This is a low-growing many-branched shrub with narrow dark-green pointed leaves 12-24mm long by 2-4 mm wide, those at the base of branchlets are more oval, about 10mm by 6mm. The leaves also become narrower near the tips of branches. This species is found on the Volcanic Plateau and Mount Taranaki.
Toxicity: mixed sample 0.02
(Turoa, Tongariro. Photo: (c) Mike Thorsen, NZPCN.)
 Coriaria sarmentosa. A large, many-branched shrub growing a metre or more high in open and disturbed locations. It can spread over wide areas, but dies back in the winter. It has long, glossy-green oval leaves 40-50 mm long on very short flat petioles (not more than 2 mm long). Found in the North, South and Stewart Islands, from coastal areas to higher altitudes.
Toxicity: leaves 0.04 to 0.23; stems 0 to 0.02.
(Corner Creek, Palliser Bay. Photo (c) Jeremy Rolfe, NZPCN.)
Toxicity
For all species of tutu, every part of the plant is poisonous, except the juice from the berries (but the seeds they contain are particularly deadly so have to be carefully filtered out of the liquid). The toxicity also extends to the honeydew excreted by the passion-vine hopper (Scolypopa australis – an arrival from Australia pictured in the gallery below which feeds on the sap in the branches) – the honey produced by bees which have collected the tutu honeydew can cause severe illness. This has at times been a particular problem affecting homey produced in the Coromandel Peninsula, Eastern Bay of Plenty and Marlborough regions. Robert Vennell (The Meaning of Trees, p. 99) notes that since 1899 there have been 141 cases of people becoming ill from toxic honey, and four cases of death. HP Connell, Poisonous Plants p. 58, cites evidence that people are more likely to be poisoned by tutu-contaminated honey than animals. In addition to tutin, the toxic component isolated in tutu itself, the contaminated honey includes a second toxin, hyenanchin, found in the honeydew but not in the plant.
The effects of tutu poisoning are dramatic: giddiness and delirium, followed by violent spasms which may dislocate the joints, after which the victim may enter into a comatose state followed by death. Even recovery from a less severe encounter may result in general debility and memory loss.
Māori were well aware of the effects of tutu poisoning, and had some remedies for countering the symptoms, including burying the patient in sand with just the head above ground to counter the effects of the convulsions, plunging them into freezing water to reduce blood pressure to slow the progress of the toxin through the system, and various methods of inducing vomiting to completely remove the toxins from the stomach.
 The most numerous human victims seem to have been 19th-century settlers and their children poisoned by eating the delicious “berries” without taking care to avoid the seeds – either directly from the plant, or cooked in pies and jams. The berries are in fact swollen petals containing the delicious juice, as can be seen in the illustration on the left, and are the only part of the plant which is not poisonous, but the seeds which they surround are lethal.
Unfortunately, unlike karakin, the toxic component of karaka kernels, the neurotoxin in the tutu is not destroyed by heat. Robert Vennell relates a 2015 account of a tramper who mistook a tutu shoot for the edible shoot of the pirita (kareao), and cooked it with other vegetables for dinner. Although he spat it out because of its unpleasant taste:
Later that night he turned blue, began foaming at the mouth and was racked by seizures that were so violent they threw his arm out of its socket. He was rushed to hospital and very fortunately made a full recovery. (P. 99)
Although people have by now generally become aware of its dangers, cattle still fall victim to the toxin, sometimes unaffected by plants encountered on their home farm but poisoned by wild plants on roadsides or in new environments. Circus elephants have also been poisoned by tutu – two fatally in the 1860s and 1957 respectively, and two others saved by injections of barbiturates in the 1960s. Losses of domestic stock, especially cattle, are still reported, but far less than in the late nineteenth century when losses of 25 to 75% of individual herds were reported. Goats, horses and unfortunately also rabbits and rats seem to be unaffected.
The New Zealand plants are not mentioned in Nelson and Balick’s Handbook of Poisonous and Injurious Plants, although they do feature the American myrtle-leaved sumac, Coriaria myrtifolia. Its toxin, coriamyrtin, seems rather benign in comparison with tutin – poisoning is most common from “ingestion of the berries”, usually without ill effects but nevertheless “substantial ingestion causes excitatory neurological effects including seizures” (p. 130). The treatment recommended is “gastrointestinal decontamination” with “rapidly acting anti-convulsants such as diazepam” to be administered if seizures result.
Beverages: Wai puhou and tewe.
Juice for drinking was treated similarly to Tītoki berries, sieved through harakeke and other plant fibres. Māori were well aware of the presence of the toxin, which they named huarua, and were very careful to ensure that no seeds were mixed with the juice. The filtered juice was known as wai puhou, and was a favourite refreshing drink, alone or mixed with water. It could be made into a sort of jelly cooked with the karengo seaweed, or used as a flavouring by mixing it with pounded tree fern pith.
Although tutu wine prepared carefully along standard winemaking principles seems to have been comparatively benign in its effects, judging by enthusiastic 19th-century accounts, left to ferment unaided, wai puhou developed into a bitter-tasting and perhaps intoxicating brew known as tewe, reminiscent of the bitter taste of the tubers and juice of the “Canoe plant” with that name (see the page on proto-Polynesian *Tewe for more information about that plant). This may have been the wine sampled by Bishop Henry Harper (Anglican Bishop of Christchurch from 1856 to 1890) and his Māori Missioner Canon James Stack, which, according to the Canon’s account relayed in Laing and Blackwell's Plants of New Zealand (p.242), resulted in both gentlemen losing all feeling in the extremities, experiencing a sensation of falling, and an obscuring of their vision, although fortunately they soon regained feeling in their feet and recovered unscathed by the experience.
Tewe may also be the referent in this rather ambiguous whakatauākī (proverb):
Ki te inumia weratia te tutu, ka rore.
If the juice of the tutu is drunk while it is hot, you'll get giddy. (M&G #1359)
This proverb is very similar to (and perhaps a copy of) one applying to karaka berries. Mead and Grove (p. 223) interpret it similarly, as an injunction to consider the possible outcomes before acting -- sloppily filtered tutu juice or the fermented tewe, like inadequately cooked karaka kernels can have unfortunate and perhaps fatal consequences for the consumer.
Other Uses: Ecological, Medical and Musical
According to Alan Clark (The Great Sacred Forest of Tāne, p. 97) tutu is one of the shrubs with nitrogen fixing properties that are part of the regeneration cycle after vegetation has been burned. This is perhaps reflected in Māori tradition which names tutu as one of the first plants to appear on the earth after the separation of Rangi and Papa. Others in that group, tumatakuru, kareao, and tataramoa, comprise ngā taero o Kupe which have conspired to block the way of many a traveller attempting to enter virgin forests in Aotearoa.
The plant had some medical uses, despite (or perhaps because of) its toxicity – it seems the sap was able to both induce and cure madness. The jelly made with the fruit could be used either as a dessert or a laxative. Other uses, both internal and (more often) external are mentioned by Alan Clark (Great Sacred Forest, pp. 324-5) and Murdoch Riley (Herbal, pp. 485-8). Leaves and shoots were used as dressing for wounds and in lotions. The juice of berries of a related species in South America was used as ink for several centuries after the Spanish occupation, and the soot of tutu bark mixed with shark, weka or tree oils was used to ensure indelible markings in moko. Red and black dyes were also produced from the bark.
The easily hollowed stems were also useful for making kōauau (traditional Māori flutes). There is an example in the Auckland Museum, and I have seen specimens made by students in a traditional culture course at Auckland University. I have heard no reports of ill-effects suffered by people who played these instruments – although Robert Vennell (The Meaning of Trees, p. 101) notes that there have been cases of players suffering mild poisoning, and mentions research suggesting that perhaps the tutu stems were deliberately used to enable the player to enter a shamanic state. Presumably the flutes were more likely to produce a “high” than a full-blown seizure.
Tutu in Proverbs and Poetry
The young, succulent shoots of tutu are mentioned as one of the harbingers of Spring (a season in this case devoid of promise) in a lament by Wharerakau of Ngati Porou for her husband Pouterangi, a notable chief killed in revenge for the death of one of his slayer's relatives as the hands of a war party (NM 1, 15, lines 13-16).
E kore rā e houa i te pō wānanga, ē ū ē,
I te pītau tutu, i te kōwhai angaora;
Tāria e ahu mai ki tō waitohunga, ē ū ē,
Ki tō whakapapanga i waiho i muri nei, ē.
Peace will not come with the white clematis blooms,
Or the young tutu shoots or the kōwhai flowers.
Do not hasten to come to your chosen mate,
Or to the young ones you have left behind you.
One proverb concerning tutu has been mentioned in the section on tewe, above. Two others are contained in the Mead and Grove collection. One likens the ripe berries to the sight of split eels drying in the sun:
Me te whata raparapa tuna e iri ana te tutu.
The tutu berries are hanging like split eels on a frame. (M&G #1914)
The other notes that famous (or notorious) people will not be able to disappear into the bushes and vanish from sight and memory:
Tō mate kei te rakerakenga tonu, tē ai he pū tutu hei hunanga.
Your death will always be exposed to view and will not be hidden behind a clump of tutu shrubs. (M&G #2543)
Coriaria arborea v. arborea - Tutu (Aotearoa)
(Branches of mature shrub. Photo: P. B. Heenan, (c) Landcare Research.)
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Colubrina asiatica - Tutu (Rarotonga, Tahiti)
(Leaves, flowers and fruit. Photo: (c) Gerald McCormack, CINHP.) |
Scolypopa australis- Passion-vine hopper.
(Nymph, greatly enlarged. Photo: (c) Phil Bendle.)
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Scolypopa australis- Passion-vine hopper.
(Adult, on tutu twig, Photo (c) Phil Bendle.) |
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