The Central Heath of the North Island.

On the pumice-covered tableland towards the centre of the North Island the heath changes its character. Certain of the northern plants are wanting, and some peculiar to the region, or nearly so, appear. Here is that exquisite shrub, Gaultheria oppositifolia, with a profusion of flowers like a glorified lily of the valley. Here also is a peculiar brownish-leaved shrub of the heath family, Dracophyllum subulatum. Manuka is, of course, in abundance as usual.

In 1886 the eruption of Tarawera led, to the burying of large areas of this plant society by volcanic ash. So thickly did this fall that in some places an actual new land-surface was formed for repopulation. This was of great interest, since opportunities for observing the settlement of a large area of virgin soil under natural conditions are rarely afforded; and in this case there is a clue to what may have taken place long ago in the evolution of the plant-covering of the adjacent country.

Where the heath was but thinly covered, it has reappeared almost in its original form; but where the covering was many feet in depth there is quite a different story. Very shortly after the eruption heavy rain occurred, and the comparatively loose soil was cut into innumerable deep but narrow gullies, with many lateral ones opening into them. The sharp ridges between these gullies are bare, but on their sides wave masses of toetoe grass (Arundo conspicua), a plant not very abundant in the adjacent heath. The "seeds" of this grass would, of course, be brought by the wind. Another common member of the new society is the tutu (Coriaria ruscifolia), its "seeds," of course, having been brought from the plants of the adjacent heath by birds.