New Zealand Plants and their Story
The Subalpine Scrub
The Subalpine Scrub.
In many places on the high mountains in New Zealand, especially in a part where the rainfall is excessive, upon emerging from the upper forest one is confronted with a formidable natural fence, many chains in breadth, dividing the forest from the meadow land. On certain mountains this belt is absent, or represented by stunted beechtrees or isolated patches of shrubs. The above barrier, composed of a thick and varied growth of shrubs, is designated the "subalpine scrub," and if unprovided with a. track is virtually impenetrable (fig. 21). The shrubs, dense in themselves, have such wiry or rigid branches interlacing into one another that no passage can be made between them. In many places where it is impossible to crawl on one's hands and knees beneath the close mass, the only alternative is to walk upon the top.page 56
At first sight it might seem that such plants would be worthless for garden purposes, and yet they are the very élite of the New Zealand flora. The scrubs of the montane and subalpine river-beds and terraces may also be included here.
Fig. 23.—Olearia nummularifolia. Subalpine Scrub of Mount Ruapehu.
Lands Department.] [Photo, L. Cockayne.
Other plants of the daisy family are the cassinias, C. Vauvilliersii and C. albida, this latter being confined to the Kaikoura and neighbouring mountains. To the same family belong also the shrubby groundsels, very common plants of the subalpine scrub, such as Senecio elaeagnifolius, S. Bidwillii, S. cassinioides, and S. Monroi.
The heaths are represented by various species of Dracophyllum and by Archeria Traversii and Gaultheria rupestris, the latter to be recognised by its lily-of-the-valley-like flowers, after the manner of those of G. oppositifolia of the central heath.
Dracophyllum Traversii is a magnificent small tree, with smooth, naked, brown stems, crowned at their extremities with rosettes of stiff, reddish leaves, having long-drawn-out points arching downwards. The subalpine flax (Phormium Cookianum), also a plant of sea-cliffs, is common, as is also, in some localities, one of the speargrasses (Aciphylla Colensoi, var. maxima), a most formidable plant with bayonet-like leaves a yard long.
Little can be said here regarding the adaptations of the members of this society. Like subalpine plants the world over, their surroundings, notwithstanding an abundant rainfall, demand protection against drought. A dense, felt-like mass of hairs is frequently present on the under-surfaces of the leaves. Very leathery leaves are common, and these have a special internal structure to account for their leatheriness, which is of advantage to its possessors. Other adaptations similar to those found in the before-described heath plants are frequently present.