The alpine flora of New Zealand is vastly different from that of the lowland areas, and also vastly different from the mountain flora of other countries. Alpine plants are fascinating for the variety of their leaf forms and for the clear colour of their flowers, though in New Zealand their colour is usually white, cream, or yellow, the flowers being produced in great profusion. An alpine meadow in January is a beautiful sight with masses of large white cups of Ranunculus lyallii and the large daisy-like flowers of Celmisias. Both North and South Islands are mountainous, the latter extremely so, with the Southern Alps running almost its entire length. The snow line is the main factor determining the distribution of mountain plants and this varies greatly according to aspect and climatic conditions. At an average of 5,000 ft altitude a new type of vegetation appears, together with an abundance of certain plants seldom seen at lower levels. There are about 500 species of flowering plants found only in the mountains; with others, the total of mountain species is about 950.
The lowland rain forest is gradually replaced by shorter trees which become more and more stunted in growth and these give place to subalpine scrub. Shrubs of divaricating growth-form and those with stiff spiny leaves form dense masses which are almost impenetrable. Above this region are tall tussocks, herb fields, and alpine plants. The latter are often very small, only a few inches high, with inconspicuous greyish leaves, but beautiful flowers, found growing in small valleys or in the shelter of rocks.
At different levels are representatives of the lower groups of plants; fungi (especially in Nothofagus forest), lichens, mosses, and liverworts, also lycopods and some ferns, as species of Asplenium on limestone screes.