New Zealand Plants and their Story
The Chatham Islands and their Plants
The Chatham Islands and their Plants.
At a distance of about five hundred miles from the coast of New Zealand, and almost due east from Lyttelton, lie the Chathams. This group has a flora quite as interesting as its subantarctic sisters, but, owing in part perhaps to the milder climate and more northerly situation, of a different character. Subalpine meadows, fields of herbaceous plants, rata forests—all these are absent. A forest of another character flourishes, distinct, too, from any other of New Zealand. The trees have a very familiar appearance; they look old friends, but are somewhat different. Surely this is the well-known koromiko; but never did one see that as a tree 50 ft. in height. Here is the lancewood, but where is the well-known juvenile form? Here, too, is the korokia of the north, yet its leaves seem larger and its yellow fruits bigger. The truth is that long isolation from the mainland has, in some way or another, led to slight differences between many Chatham Island and New Zealand plants. They have certainly come from a parent stock—perhaps one or the other is the actual parent; but now, although closely related, they are for the most part distinct species. The lancewood is neither Pseudopanax crassifolium nor P. ferox —it is P. chathamica; the koromiko is not Veronica salicifolia —it is V. gigantea; while the korokia is named Corokia macrocarpa, and in its larger fruit and broader leaves is distinct from C. buddleoides of the North Island.page 121
There is no shrubby undergrowth in the forest, but tree-ferns and ferns of all kinds are very abundant. The only lianes are the supple-jack, the climbing-convolvulus (Calystegia tuguriorum), and Muehlenbeckia australis. Many most characteristic New Zealand forest-trees page 122are quite absent—e.g., all the taxads, the beeches, the palm-lilies, and the pittosporums.
In the neighbourhood of these olearia bogs the margin of the forest often consists entirely of the rautini (Senecio Huntii), a mag-page 123nificent tree-groundsel, which produces immense bunches of yellow flower-heads, and has aromatic pale-green leaves in semi-rosettes at the ends of its stiff, bare, brittle twigs. For many hundreds of yards at a time this belt extends, forming, when covered with its golden blossoms, a gorgeous mass of colour.
The most famous of all the Chatham Island plants is the giant forget-me-not (Myosotidium nobile) (fig. 1), frequently called by the absurd name of Chatham Island lily, or, what is worse, Macquarie cabbage! This wonderful plant, found nowhere else in the world, is now almost extinct. Formerly it extended almost round the main island, forming a broad belt on the sea-shore, just above where the dry page 124seaweed marks the high-tide limit. The massive, shining, broad, green leaf-blades, a foot or more in length, raised high from the ground on stout leaf-stalks, and the numerous blue flowers, each half an inch or so in diameter, render this plant a most conspicuous object. The seeds germinate rapidly if fresh, and seedlings are raised with the greatest ease. The writer has long thought this noble plant might easily be naturalised on our northern sea-shores—for instance, on the Little Barrier and on Kapiti. Surely some effort could be made to fence a piece of the Chatham Island shore from sheep and pigs, so that this rare and interesting plant could once more reassert itself in its natural station.
Other interesting Chatham Island plants are the mutton-bird plant (Cotula Featherstonii), which grows only near the holes of the petrels; the shrubby speedwells, Veronica Dieftenbachii, V. Barkeri, and V. chathamica, this latter a charming little plant, of which there are many distinct forms, which creeps over rocks close to the sea; the great sowthistle (Sonchus grandifolius), which grows on sand-covered ledges of rock near the sea, or at times on the dunes; the bog-grass, Poa chathamica, an important fodder plant; the Chatham Island cranesbill (Geranium Traversii), of which there are white and pink varieties; the swamp-matipo, Suttonia Coxii, with its pretty mauve fruits; the gentian, Gentiana chathamica; and two spear-grasses, Aciphylla Dieffenbachii and A. Traversii.
Settlement has in many places quite changed the face of the country. In some places are fine grass paddocks, in others the bracken-fern and the piripiri (Acaena novae-zealandiae) have become weeds. Phormium tenax was originally very common, but is now a thing of the past in most cases. The Chatham Island variety differs from any in New Zealand proper in its broad and rather drooping leaves and their weak fibre.