Variation and Distribution of the Mixed Forest.

The mixed forest varies according to latitude and altitude, but a general groundwork of plants is always present. Many northern forms are wanting in the south, and, conversely, the more important southern species are less frequent in the north at a similar elevation. Latitude 38° forms a fairly definite boundary for quite a number of trees and shrubs, and latitude 42° a second boundary, though, the former, and to a greater extent the latter, is overstepped in several instances.

The pines (species of Podocarpus and Dacrydium), as they are popularly called, but more correctly designated taxads, since they are related to the yew (Taxus), are everywhere important members of the society under discussion. Confined to the north are—the taraire (Beilschmiedia tarairi), the mangaeo (Litsea calicaris), the makamaka (Ackama rosaefolia), the tawhero (Weinmannia sylvicola), the toatoa (Phyllocladus glaucus), and, some other trees and shrubs.

Amongst the trees not spreading much beyond latitude 42° are some very common ones of the northern forests. Some of these are—the karaka (Corynocarpus laevigata), which reaches Banks Peninsula; the tawa (Beilschmiedia tawa); the kohekohe, or New Zealand cedar page 47(Dysoxylum spectabile); the rewarewa (Knightia excelsa); the pukatea (Laurelia novae-zelandiae); the tanekaha (Phyllocladus trichomanoides); and some of the New Zealand olives.

The southern mixed taxad forest extending from latitude 42° to the south of Stewart Island is distinguished rather by the absence of the northern plants than by any peculiar species of its own, though such are not lacking. The Town Belt of Dunedin consists of a remnant of such a forest, and small pieces still exist all over the east of the South Island. But in the west and south the ground is still occupied by mighty forests, which for luxuriance of growth, wealth of ferns, lianes, mosses, and liverworts can hardly be surpassed. Here, too, many plants found in the North Island only in the subalpine region occur at sea-level.