Tea_Tree_Picture

New Zealand Tea Trees.
Leptospermum scoparium (Manuka)
Leptospermum ericoides (Kanuka)
Compiled and introduced by Ivor Hughes.

Plants of New Zealand � 5^th Edition Revised,
by
R.M. Laing, B.Sc., F.R.S and E.W. Blackwell (Mrs. Thomas Maidment)

New Zealand is a blessed land and no more so than in its Native Sons and Daughters both Maori and Pakeha. This little gem of a book is long since out of print but it is a classic work both of scholarship and its love of subject which shines forth in its treatment of the New Zealand Flora. A labour of love. The authors introduce their work with the following verse;

�Oh when I am safe in my sylvan home, I tread upon the pride of Greece and Rome, and when I am stretched beneath the pines, Where evening star so holy shines, I laugh at the lore and pride of man, At the sophist schools and learned clan, For what are they in all their high conceit, When man in the bush with God may meet�.
R. W. Emerson.

Calder, Cole and Walker¹state that both species of Tea Tree; the Red Tea Tree and the White Manuka contain antibiotic substances effective against; E. coli. S. aureus. B. sub. C. alb. E. floc. These species of micro organisms are now resistant to most of our synthetic armament but we may rest sure in the knowledge that Nature in her fecundity caters for all our needs. Manuka is the Maori name for the Red Tea Tree for which the image is shown of the flowering tops. The ripe seed capsules were chewed by the Maori as an astringent. The timber is much esteemed as firewood and burns with an intense heat reminiscent of Hawthorn which was used in Britain to smelt iron. The volatile oil is obtained from the young tops by means of steam distillation. The volatile oil and the honey from its flowers brings a premium price and enjoys a global demand for its health giving properties.

1. Victoria L. Calder, A. L. .J. Cole and J. R. L. Walker. Antibiotic compounds from New Zealand plants. Journal of the Royal Society of New Zealand Volume 16. Number 2. 1986. pp 170 � 171.

�Plants of New Zealand � 5^th Edition Revised,
Myrtaceae
THE MYRTLE FAMILY.

Distribution A large family of about 2800 species, chiefly tropical Many of them abound in aromatic oils, while others furnish gums. The flowers of this family are very similar to those of the Rosaceae. the main distinction between them being that the carpels are more or less free, particularly in the stigmatic region, in the Rosaceae; whilst in Myrtaceae, the carpels are completely united, the union extending to the stigmas. Many of the myrtles, also, have glands in all their parts, which secrete ethereal oils that give the plants an aromatic odour. This is, perhaps, the most striking character of the family. The corolla is usually white, and the filaments, which are often a bright red, serve as the chief organs of attraction for insects. Cloves are the flower buds of a species of Eugenia. Another species of the same genus furnishes the fruit from which allspice is obtained. The guava is the fruit of Psidium guava. The only European species is the well known Myrtle. The oil of eucalyptus, obtained from Eucalyptus globulus, is antiseptic in its action. This tree is often planted, on account of its rapid growth, for the purpose of drying up swamps, and thus keeping off malarial fevers.

Genus Leptospermum.
Shrubs or trees, with alternate entire leaves. Flowers regular, white or pink. Calyx 5-lobed, petals 5; stamens numerous. Capsule woody. About 28 species, of which 3 belong to New Zealand , and 20 to Australia .

Leptospermum scoparium (The �Manuka).
A shrub or tree, sometimes 30 ft. in height. Leaves leathery, hard, with sharp points. Flowers scentless, on very short stalks, white or rosy, � in.- � in. across. Capsule bursting by 4 or 5 valves, very woody. Maori names Manuka, Kahikatoa. English name, Tea-Tree. Both islands. Fl. Nov.-April.

This is the most abundant of New Zealand shrubs. It is the colonial counterpart of the English broom and gorse, and is as beautiful as either of these. One of the loveliest sights of the land is a great valley at Christmas-time, clad with Leptospermum in full flower. From the distance of a mile or two, the country seems to be spread with a sheet of snow, so profusely does the plant flower. A variety now named Nicholsii, with dark crimson blooms, was found at Chaney's Corner, near Kaiapoi. It is a magnificent plant, and at the beginning of the Great War (WW1) was selected by the Royal Horticultural Society of London as the greatest novelty of the year. Plants were then sold at twenty-five pounds apiece.

To the Maoris the tree was known as the manuka. By the bushmen it is generally called tea-tree. It has acquired this name because early voyagers and colonists sometimes used its pungent leaves in place of tea. Indeed, the whole plant, including leaves, flowers, fruit, and young shoots, is highly aromatic, and the oil which it contains, will perhaps, in future, be put to some useful purpose.

The flowers are generally bisexual, but are sometimes imperfect or unisexual. A branch may occasionally be found bearing flowers which are staminate only, while on the lower portion of the same branch last year's capsules are borne. The capsule is hard and woody, of a reddish-brown colour. Very small specimens occasionally bear flowers. A plant was once observed, not more than half-an-inch in height, which bore a flower and duly developed seed. The flower appeared to be actually lying upon the ground.

The wood of this tree is largely used for fences and firewood. The Maoris made use of it for their paddles and spears, and a bunch of the twigs makes an excellent broom. The manuka is a most plastic plant, and can adapt itself to wide changes of environment. It may be found on mountain tops in excessive wind, dwarfed almost to a cushion plant. It grows also on the seashore, in swamps, on dry land, and on rocky cliffs. Few plants have such a wide range of habitat. It may be only a few inches high, or a tree of 25 ft. or more. It very often replaces the bracken fern, some years after a fire. It is most abundant throughout the Dominion. As a result of injuries caused by sap-sucking insects the leaves are sometimes covered with a white crystalline substance, known as manuka manna. The substance is probably a complex sugar, but so far has not been thoroughly investigated.

Leptospermum ericoides (The Tree Manuka).
A larger tree than the preceding. Leaves narrow, acute, glabrous or silky, fascicled. Flowers in. across, white, very fragrant. Maori name Manuka-rauriki, but now very often called the Kanuka. Both islands. Fl. Nov.- Jan. This is nearly, but not quite, as common a plant as the previous one. Like the former species, at high levels, in wind-swept localities, it becomes prostrate, and is reduced to a few inches in height. In suitable positions, however, it grows to be a larger tree than L. scoparium, sometimes attaining a height of sixty feet, and a diameter of one to three feet. Its timber is hard and durable, and is used for jetty piles, spokes of wheels, fence-rails, and other purposes. It is also much sought after for firewood, and this has led to the cutting out of all the larger trees over wide areas, so that in many places it is now impossible to procure it. To many old settlers, however, the odour of burning Kanuka logs brings memories of the pleasant winter evenings of times long past. Older trees of both species have their trunks covered with a light brown bark, that readily strips off, and is frequently used for fire-kindling. For the camper-out, Leptospermum provides fragrant bedding, easily collected, and not readily surpassed for comfort. There is little undergrowth in the manuka copse, and the ground below it becomes carpeted with dead leaves, almost as in a pine forest. There are, perhaps, several reasons for this lack of undergrowth. The plant often grows on poor ground; the resinous leaves may, like the pine needles, make bad mould; and the shrub itself probably exhausts the soil. Yet sometimes certain orchids are found below it, which are rare elsewhere, and various other plants seem to prefer the manuka grove as a habitat.

Mr. G. M. Thomson has discussed the probable origin of the New Zealand species. L. scoparium, with sharp leaf tips, is said to be found abundantly in south-eastern Australia *; but L. ericoides, with less pungent points to its leaves, is endemic. Mr. G. M. Thomson states that the rigid sharp-pointed leaves of the former indicate that the species originated in a land where there were herbivorous Mammalia, for he considers that "such sharp-pointed leaves are probably so developed in order that they may be as obnoxious as possible to grazing animals."!

As the genus has come to us from a northern land, where possibly marsupials and other grass-eating animals were abundant, this explanation seems feasible. It also appears to receive confirmation from the fact that the endemic species has less prickly leaf-tips than the one with wider distribution. However, there is another, and, perhaps, simpler interpretation of such sharp-pointed leaves. They may be due merely to leaf-reduction, produced as a means of protection against excessive transpiration

(v. Aciphylla, Hebe, Discaria). Indeed, that the modification, in the case of Leptospermum scoparium, is climatic rather than defensive, is shown by the fact, that, in certain mountain localities, the leaves become less rigid, more rounded, and less acute. .

* There is some doubt as to the identity of the local and Australian species, � New Zealand Journal of Science, Vol. II., p.