In the large island of Tha-na-Mawi there are immense forests of Lianes and interlacing shrubs, which render them impenetrable. In these forests there exist, no doubt, trees of gigantic dimensions, for the canoes of the natives are sometimes as much as sixty feet long, and from three to four broad, all hollowed out of one trunk. At from two to four miles from the coast Messrs. Richard and Lesson saw large spaces, very low and probably marshy, covered cuprés- with great masses of: green trees, of which the Dacrydium sinum and Podocarpus dacrydioides, and some others, form the principal species. The vegetation of the harbour where the Astro; labe lay was very beautiful, although the number of cryptogamous: ‘

plants almost equalled that of the Phanerogames. The European is surprised to meet there many vegetables from home, or closely allied to them, such as Senecios, Veronicas, Rushes, the Acrid Ranunculus, &c.;and, on the other hand, several unknown yege-tables, particularly those of New Zealand, grow abundantly in these localities, such, amongst others, as the Phormium tenaz, called by Europeans New Zealand Flax, because its fibres furnish a very strong thread, very much used in the manufacture of certain fabrics. Ferns form almost a seventh of the whole vegetation of this country. Among the monocotyledons are the Graminew and Cyperacew. Among the dicotyledons the Umbellifere, Crucifere, and (Hnothere. New Zealand only furnishes a small number of alimentary plants. The aboriginal inhabitants of this archipelago, for the most part icthyophagons, were long reduced to the fecculent root of a Fern, the Pteris esculenta, for food, when they could not obtain fish. None of their trees produce large fruit. The Taro or Caladium esculentum and the Sweet Potato (Convoloulus batatus) also. serve as nourishment to the inhabitants of these countries. It is to be remarked that European vegetables, introduced _ into New Zealand by sailors, are propagated there with such facility that the aspect of the ground, as well as conditions of life, are greatly modified. Amongst the vegetables proper to the archipelago in question we may note the Corypha australis amongst the Palms, arborescent Draeznas, forests of Conifer, with large leaves, the Dammara, and Metrosideros amongst the Myrtacezx.

Mountain VEGETATION.

We have briefly traversed the principal botanical regions of the globe; and in the course of our survey, we have seen that vegetation changes with the latitude: that is to say, according to the distance of the equator. As we advance from the equator, towards the poles we meet in succession with the equatorial, tropical, temperate, and polar zones—vegetation gradually losing its power, a fact which is proved most satisfactorily by the decreasing number of species and by their dwarfed appearance, until vegetation _ altogether ceases in the region where snow reigns eternal. When heat disappears organic life is —— and _yege-— See:

table organisation is subject to the same laws, and experiences loss of power and vigour proportioned to the decrease of heat.

But a natural reflection presents itself immediately, as a corollary upon these remarks. When we ascend a mountain, or, in fact, when we ascend by any means whatever,—in a balloon, for instance, as Mr. Glaisher’s experiments seem to show,—the temperature decreases by something like one degree for every hundred yards above the surface. It follows from these premises that every stage in the ascent of a mountain should exhibit different forms of vegetation, each forming a zone or botanic region, similar to those we have passed in tracing their geographical latitudes. And this is so in fact, as we shall find in the following remarks, which we borrow from the writings of Adrien de Jussieu on the vegetation of the Alps, Professor Ch. Martin, on Mount Ventoux in Provence, and Dr. Hooker, on the Himalayas:— “ Let us imagine a spectator at the foot of the Alps,” says M. de Jussieu, “ opposite to oneof those grand rocky masses crowned with eternal snow. As his eye ranges along the sides of the mountain, he observes that the vegetation which immediately surrounds him, and which is that which characterises central and northern France, disappears at a certain height, giving place to another, which in turn disappears at a higher range. Beyond a

certain distance the eye can only seize the masses indicated by large trees, the humbler plants being concealed behind them, 80 that they look like a series of bands superposed one over the other on the slopes of the mountain. At first these belts are composed of deciduous-leaved plants, which drop early, and are readily distinguishable by their more tender verdure, than conifers of deeper green, which in the mass appear nearly black. Another belt succeeds of an undecided green, interrupted here and there by clumps of another colour, which goes straggling up to the sinuous line where the snow commences. This is owing to the circumstance that the trees whose branches are too closely inter-mingled have died out, making room for shrubs or herbaceous plants, more dwarfed in their growth, and more on a level with the soil.. ae “Tf the spectator approaches the mountain and scales it, he will ae:

find other plants, very different from the masses he looked at in the distance, which we call Alpine plants—such as the Aconites, Astrantia, certain species of Artemisias, of Groundsel, Prenanthes, Achilleas, Saxifrages, and Potentillas. After having skirted the Walnut-trees, and traversed the woods formed of Chesnut-trees, these will be observed to cease, and forests of Oaks, Beeches, and Birches take their place. Of these, the Oaks disappear first, at the height of about two thousand five hundred feet above the level of the sea, the Beeches about three thousand. Beyond this the trees consist entirely of evergreen trees, as Firs, Larches, and the common Pine, which stop also at certain successive stages, about four thousand five hundred feet. The Birch ascends a little higher, but disappears also at about six thousand feet of elevation. A conifer (Pinus cembro) continues for another hundred yards. Beyond this limit the trees become dwarfed in size; for example, a species of Alder (Alnus viridis) becomes a low shrub. Near to this the botanist will find himself surrounded by shrubs very characteristic of the Alps, sometimes called the Alpine Rose, namely, the Rhododendron, which ceases in its turn only a little higher, giving place to plants © much more lowly, which scarcely rise above the soil. These are specially known as Alpine plants. They belong to families which he observed at his point of departure. A few Crucifers, Caryophyl-lum, Rosacexw, Liguminosex, Composite, Cypriacexe, Graminex, but of different species. These also are numerous, and with them of other families which rarely show themselves in representatives the plains, such as Saxifrages, Gentians. Annuals cease almost entirely, as might be foreseen, since an unfavourable season, in which the ripening of their seeds was checked, would be sufficient to destroy their race.’ The roots of perennial or woody plants bury themselves under the soil, where a higher temperature is preserved. They submit and develop them- to the influenceof the atmosphere themselves warm. But this can only selves when it is milder and sufficiently be done during a short season, and on some places only once in many years. It follows that the stems are short and scarcely usually hug rise out of the soil, while those that are frutescent raising short, hardy, sometimes creeping, sometimesthe ground, stems, forming thick stunted bushes, as would resultintertwining

in ordinary cases from pruning shrubs very near the ground. The general appearance proper to the plant is thus effaced in some respects, and replaced by the physiognomy belonging to Alpine vegetation. These plants are generally of the arborescent kind, like the Willows, whose roots creep along the ground. The more elevated they are, the more scattered and impoverished is the vegetation, until, at the foot of the rocks, it only appears in the form of lichens, whose crust differs little from the monotonous tint of their own surface. When the limit of eternal snow is reached, organised life can no longer exist.

Mount Ventoux, in Provence, presents us with an interesting application of the same facts. This mountain rises abruptly from a _ plain, the temperature of which maybe compared with that of Sienna, Brescia, or Venice, while the summit of the mountain approaches the climate of Sweden, on the borders of Lapland. To ascend its sides and reach the summit, is as if we had actually traversed nineteen degrees of latitude, or from 44° to 63°. Professor Charles Martinshas published an interesting accoutit of the vegetation of this mountain. ‘ Mount Ventoux,” says the learned Professor of | Montpellier, “presents a succession of well-defined botanical regions, each characterised by the presence of plants which are wanting on the others. These regions are six in number upon the southern — slopes, and five on its northern side. “‘ Ascending the southern slope, its base, in respect to its vegetation, is like that of the valley of the Rhone. All the plants of the _ plains are found in the region at the foot of the mountain, and they are well characterised by two trees—the Aleppo Pine and the Olive. Both belong to the basin of the Mediterranean, round which they form a girdle, only interrupted by the delta of the Nile. The- Aleppo Pine is found upon all the hills which lie at the southern foot of Mount Ventoux, but ceases at the height of fourteen hun- — dred feet above the level of the sea. The Olive ascends a little higher, but ceases also at sixteen hundred. Under these trees we meet with all the species which characterise the vegetation of Provence. The Kermes Oak, the Rosemary, the Spanish Broom, — 2 and Dorycinium suffraticasm. ‘A narrow zone scarcely exceeding ® | hundred and eighty feet succeeds to this, which is characterised by the evergreen oak. Among the under-shrubs we find the wage

European Leadwort, the Juniper, the great Lurphorbia eharacis, the Psoralea, of bituminous odour, &e. “A region altogether destitute of arborescent vegetation follows. The soil is here naked, stony, and generally uncultivated; nevertheless, here and there fields of chick peas, oats, and barley appear, the last of which disappears at three thousand five hundred feet above the Mediterranean; but a shrub—the Box Tree—two undershrubs—Thyme and lLavender—another herbaceous Labiate (Nepeta graveolens), and the Swallow-wort (Vincetoxicum officinalis), predominate as to size and number. | It is at this point that the first indications of an arborescent vegetation appear, but it is necessary to ascend to three thousand eight hundred feet before reaching the new vegetation. It is composed of Beeches; at first. sparse and undersized, they get larger three hundred feet higher, especially in the deep ravines and valleys, where they are sheltered from the wind. This region extends as high as five thousand five hundred feet. At this height the depressions: are slight; valleys and ravines almost cease, and the trees are ex tothe depressing action of the winds. The plants which clothe the soil are now humble bushes, with! short, hard, and crowded ~ branches. One of these bushes, like a large ball or mattrass extended on the earth, is often as’ old:as the great Beeches which elevate their proud heads to the heavens in the valleys below. ‘Numerous species occupy the regionof Beeches, many of them belonging to the sub-alpine zone of the mountains of central Europe, never descending into the plains, unless transplanted. Such are ' the Buckthorn, the Gooseberry, the Wallflower, the Mountain Sorrel, and the mountain Anthylis.

“At the height of five thousand six hundred feet the cold is intense, the summer brief, and the wind so violent that the Beech can no longer exist. As upon Mount Ventoux, so it is on the Alps and Pyrenees,—on all, a tree of the family of Conifers is the last representative of arborescent vegetation. Itis a humble species of pine, called the Mountain Pine (Pinus uncinata), because the scales of its cone are curved into a sort of claw. These Pines are found many feet in height in sheltered places, but become mere bushy shrubs when exposed to the sweep of the winds. They ascend as high as six thousand fect, the extreme limit of arborescent vegetation.

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