NEW ZEALAND FLORA

Forest and Bird, Issue 42, 1 November 1936, Page 3

NEW ZEALAND FLORA

(By B. C. Aston.)

ITS ROMANCE AND ITS VALUE

POOR as are the islands of this Dominion in food plants compared with those of other Pacific Islands, there is yet a history of the application to human wants of New Zealand plants as romantic as it is interesting. Fern root (Pteridium aquilinum, var, Esculentum) was the main indigenous farinaceous food of the Maoris and was, doubtless, troublesome to obtain and more troublesome to chew, but it developed a mighty race of big, muscular men who had not a superfluous ounce of fat, —valiant and unafraid of Cook’s huge ship and strange weapons which dealt such unusual blows. The cultivations of the Maoris included the sweet potato or kumara (Ipomoea batatas), the taro (Colocasia antiquorum), and the gourd, hue (Lagenaria vulgaris), all of which were brought from the Polynesian Islands. Perhaps the constant firing of the country, which was evidently a feature of their life, judging from Cook’s numerous observations, was intended to clear the way for the growth of more fern root. Besides this food they had also many subsidiary plants which furnished sweet mouthfuls of sugary - matters. Straining off the poisonous seeds, they made from the juicy tutu fruit a sweetened drink. The female flowers of the kiekie (Freycinetia Banksii) furnished another food and, growing in many of their settlements are, even now, a variety of the Cordyline australis, or cabbage tree, which yielded very sweet tasting roots and stems. The trunk of this cabbage tree was so elastic that the top tuft of leaves could be pegged down to the ground. ’When new rooting had taken place, the trunk and original roots were eaten. This variety, botanically undescribed, was called ti-para, and was not the Cordyline ter minals (ti-pori), and is distinctly worth cultivating in gardens, as it sustains its juvenile state longer than the ordinary Cordyline australis, and has larger leaves and grows readily

from cuttings.

THE KARAKA TREE AND FRUIT.

In the karaka fruit the Maori found a fruit which, in season, furnished a date-like pulp;

and the large kernel, when baked and steeped in running water to dissolve out the poison, provided a very welcome change as a vegetable food from fern root or kumara.

This is one of the best known instances of the ingenuity of the Maori in overcoming difficulties which would seem insuperable to most primitive people. In the uncooked state the kernel is such a deadly poison that even one when eaten will produce severe convulsions. It is said that when children were poisoned it was necessary to bury them up to the neck in sand in order to prevent subsequent permanent distortion of their limbs, an impossible effect according to physiologists. Since the coming of the Pakeha, chemists (Skey, 1871; Easterfield and Aston, 1901) have isolated the poison and find that heating the kernel changes the poison into a substance

which is very soluble in water and can be eliminated by washing, thus confirming the Maori method of treating the kernel to secure a valuable foodstuff.

For the benefit of those interested in chemistry, it may be explained that the kernel apparently contains what is known to chemists as a Cyanogenetic glucoside, i.e., a poisonous principle which is capable of generating hydrocyanic or prussic acid. The crystalline principle “Karakin” is itself non-poisonous but, when eaten, substances in the kernel (possible enzymes) act on the compound and liberate other compounds which are poisonous, exactly as in the case of the poisonous bitter almond. The karaka (Corynocarpus laevigata) is a tree limited to Polynesian and Melanesian distribution. It is probable that the Maori planted it as, although naturally a coastal tree, it is found along the Wanganui River settlements. It is a tree destined to play a part in the development of this country. As it delights in sunlight, wind, and exposed situations unprotected by other trees it will, with the puriri (Vitex lucens), the pohutakawa (Metrosideros tomentosa) , and its sister species the giant rata (M robusta), and the Kermadec rata (M. villosa), be much used for street planting in coastal towns. In times of scarcity great branches of the evergreen karaka are lopped off by the settlers, providing abundance of large leaves for hungry cows, which apparently eat them without ill effect. When pigs eat the fallen poisonous fruit a slight paralysis of the posterior portion of the animal has been noticed by accurate observers.

One who remembers the magnificent clump of karaka trees which adorned the heart of Wellington City, and which, one fine morning about the year 1900, were cruelly cut down, can have no doubt as to the success of the karaka as a street tree. These must have unusual qualifications to succeed in draughty and dusty positions.

THE TUTU (Tupakihi).

Unlike the karaka the tutu ( Coriaria ruscifolia) has a world-wide distribution, for the other species of Coriaria are so closely allied that, for the purpose of this article, they may be regarded as the same plant. Under various names this plant occurs in the south of Europe, India (Himalayas), China, Japan, Central and

South America, always in mountainous localities. The Indian plant (C. Nepalensis) is, apparently, only feebly poisonous, as it is a staple green fodder for ruminants in certain districts, while herdsmen suffer but slightly after an unusually large meal of the fruit. The European (C . myrtifolia), on the other hand, is deadly, and the active principle (Coriamyrtin), isolated in 1870 by Riban, a French chemist, is similar but more toxic in its action on the animal than tutin, the crystalline principle of the New Zealand species, isolated by Easterfield and Aston in 1900.

Regarding the Chinese and Japanese plants (C. terminalis and C. Japonica) little, if anything, is known of their poisonous properties. They are grown in a few English gardens on account of their handsome appearance, and are especially ornamental when covered with bright, red fruits. The American species is least known of any, but seeds from the Andes sent the writer by Mr. Clarence Elliott are now growing in Wellington. The whole of the species would make beautiful garden plants and, but for the danger of poisoning children, should be more extensively grown, as they would undoubtedly attract birds of the right kind. The gem of the whole genus is the small New Zealand alpine, tutupapa (C . angustissima), with its delightful fern-like leaves and very large black fruit— plant that should be in every moraine garden.

Thus the two most poisonous plants in New Zealand, the tutu and the karaka, were, by the ingenuity of the native, made to supply very palatable foodstuffs. The German name of the European tutu“gerberstrauch,” “dyer’s bush” —indicates an economic use. The plant contains sixteen per cent, of tannin. The generic name “Coriaria” is derived from “Corium” leather. The possibilities of the New Zealand species in dyeing and tanning have not been determined, but it is known that they contain much gallic acid.

EFFECTS OF TUTU POISON.

The remarkable thing about the poison of tutu is that it causes those who suffer from its effects to lose their memory. The first Englishman who experimented with crude extracts on himself, and Englishmen have always been ready to experiment on their own bodies before on those of their long-suffering patients, experienced great difficulty for months, after he had recovered from the overdose of tutu, in remembering his engagements. This was Dr. W. L. Christie, one of the first M.D.’s of the Otago Medical School in 1890, whose lengthy and interesting memoirs appear in the New Zealand Medical Journal for that year.

Dr. Christie, however, did not have the advantage of experimenting with pure poison, and it has been shown by Japanese experimenters, working on the Japanese “toot,” that there may be more than one poison present. The disadvantages, therefore, of working with impure materials which contain the substances of different qualities in regard to the poisonous effects they exert is that one cannot say to what poison the results are due. Immediately the pure principle is isolated and obtainable in a pure condition, in sufficient quantities for medical research, the physicians are stimulated to undertake research work, knowing that no error can creep in from the chemistry side of the investigation. This is what happened with the New Zealand poison. As soon as it was isolated researches were started at St. Andrew’s and at the Dunedin Medical School, and also later by independent medical men on their patients. They were thus able to give as small a dose as one-thousandth part of a gramme dissolved in water in perfect security and know that the results should be attributable only to the pure crystalline tutin.

The active principle of the European “toot” has been on the market for many years, prepared by the great Darmstadt house of Merk, and found useful for stimulating the human animal after wasting diseases. If a similar use could be put to tutin, it is possible that it would be commercially satisfactory to extract tutin on a large scale and, although a beautiful plant, farmers. and landowners would be well pleased to see this menace to their herds removed from waste places where driven stock even now are often passing. It is not realised, I think, how dangerous a pest the New Zealand plant was to stock-owners in the old days when comparatively large numbers of animals perished annually. Nowadays drovers have become, by bitter experience, possessed of a superior technique in droving, whereby cattle are hurried by localities growing the plant and not allowed, for one moment, to devour, in certain seasons, the tall, juicy shoots of the plant. These seasons are spring and autumn, but, of course, for human beings the poisonous fruit is available only in the autumn.

It is astonishing what a stimulant to the blood pressure and to the whole organism tutin is! When evaporating large quantities of tutu in open vessels in the laboratory a great deal of the tutin is lost through being dissipated into the atmosphere. One only appreciates this in the confined space of a chemical laboratory, and it has been noticed that all assistants working in such a laboratory have their appetites considerably increased, presumably through breathing volatilised tutin.