There are few poisonous plants in this part of the colony.
Tupakihi, or Tutu (Coriaria ruscifolia).
As cultivation and cattle spread, this plant is rapidly disappearing. The juice of the fruit, strained free from the seed, is sweet and luscious and can be taken with impunity. The seeds are noxious. Their effect on the human subject is rigidity of the spine and neck, discolouration of the face, fixity of the eyes and general tremor. If emetics be administered cases are seldom fatal.
Cattle suffer from eating the young shoots, more especially hungry working bullocks. The effects are a temporary frenzy, a disposition to rush at any object, staggering and falling. If the animal can be approached, bleeding from the ear gives relief.
Sheep are very fond of the leaves; but as they eat deliberately, and walk as they eat, they suffer little. When a sheep is attacked by eating too much tutu, it rushes a dozen steps with protruded head, stops, staggers, and falls. Raising the head above the spine, and keeping it steady for a minute or two gives relief, and the animal resumes its usual quiet state.
A carefully-prepared paper on the poisonous principles of this plant, by Mr. Skey, will be found in “Trans. N.Z. Inst,” vol. ii., p. 153; and, in the same volume, p. 399, an account by Dr. Haast of an elephant being poisoned by eating tutu.
It is possible that the poison of the seeds might be used in destroying vermin, flies, and insects. As it affects the brain, its effects are probably painless.
Wharangi, or Pukapuka (Brachyglottis repanda).
This shrub is seldom eaten by cattle or sheep, but horses are fond of it. Its effects are staggering of the legs, and falling. It is often fatal; after death the body is much distended. The only cure known as yet is to keep the animal moving, or burning rags under its nose.
Karaka (Corynocarpus lœvigata).
Leaves and twigs are valuable forage for cattle. The pericarpium of the fruit is nutritious. The kernels of the seed are exceedingly poisonous, producing convulsions, and sometimes permanent distortion of the limbs. A graphic account of its effects is given by Mr. Colenso in Mr. Skey's paper, vol. iv., p. 316, of our “Transactions.”
Cooked and steeped in water for several weeks, these kernels formed a part of Maoris' diet, and probably were nutritious. As the ripe berries fall from the trees they are greedily consumed by cattle. Mr. Palmer, of Awhitu, writes to me: “After
eating karaka berries cattle become much excited, and lose all power in or control over their hind legs. Milking-cows are more affected than store cattle, their milk rapidly drying up.” Other settlers, on the other hand, tell me that their cattle eat the karaka berries with impunity. Probably this difference in report is owing to the quantity consumed, Awhitu having always been celebrated for its karaka groves. The karaka is a prolific bearer, and if a surer and better treatment than that of the Maori could be found, there appears to be no reason why, if perfectly deprived of their karakine, the seeds should not be an article of food.
This is a swamp grass, growing in the north of this Island. According to Mr. F. Maxwell, it is poisonous to sheep.
Puriri (Vitex littoralis), and Manuka.
May be classed amongst dangerous plants, from the severe inflammation caused by splinters penetrating the skin of hands or feet.
I have not heard of any native plant possessing this quality.
A decoction of the root is a strong purgative. In vol. 6 of “Transactions,” p. 260, appears an able paper by Mr. A. H. Church; the chapter on the “bitter principle” is instructive. This principle Mr. Church considers tonic. In an appendix is an analysis of the seed, showing that it is rich in oil, a fact not generally known; he gives the proportion of oil at 20 per cent: that is, 100lbs. weight of flax-seed would yield more than 2 gallons of oil.
Kariao, or Supplejack (Rhipogonum scandens).
A concentrated decoction of the root has a scent and flavour like that of sarsaparilla. It is sweetish, and certainly demulcent to the throat. Its qualities deserve attention.
Our flora is rich in plants of this kind—used as cures for diarrhœa, or as styptics.
Koromiko, or Veronica (V. salicifolia).
This is a well-known remedy for diarrhœa used by Natives and settlers. A few of the young leaves chewed and swallowed
afford a nearly certain remedy. I have found that an infusion of its dried leaves has little or no effect, but that a decoction has; from this, I suppose the active principle differs from tannin. Mr. Fitzgerald, of Wellington, offers a preparation of this useful plant, of which it is to be hoped the public will take advantage.
Rata (Metrosideros robusta).
The juice of the vine, obtained by cutting and inverting it, affords a strengthening, slightly astringent, beverage; very wholesome.
Pohutukawa (Metrosideros tomentosa).
The inner bark is reported to be useful for diarrhœa.
Rimu (Dacrydium cupressinum).
The gum of this tree is excessively astringent. The bark of the young tree was used by Maoris as a styptic, to stop the bleeding of wounds.
The capsules of Manuka (Leptospermum scoparium), and the gum of Cyathea medullaris (Punga), are also useful in attacks of diarrhœa.
Kawakawa (Piper excelsum).
Its effects are stimulating; it excites the salivary glands, the kidneys, and the bowels slightly; it is aphrodisiack. The fruit and seeds, ripe or unripe, are more powerful than the leaves, although the latter are generally used. Mr. Fitzgerald has also prepared an extract of this plant.
Kohekohe (Dysoxylum spectabile).
The leaves and bark of this tree are intensely bitter; it is not eaten by cattle or sheep. A decoction of the leaves, if not too concentrated, is agreeably bitter. I consider it a tonic, but the opinion requires confirmation.
It is not likely that a drug of specific value will be obtained from our plants; but I think there is material for the preparation of some useful medicines, to which pharmacists, following the example of Mr. Fitzgerald of Wellington, may find it their interest to attend.