98 NEW ZEALAND PLANTS. 
thereto. This happening is not unexpected, since there is far more 
room for high-mountain species in the latter Island, and many species 
undoubtedly of recent origin have not yet had time to spread far. 
The total North Island high-mountain flora numbers fewer than 180 
species, of which only about 35 are confined to that Island. Finally, 
a considerable number have gained a permanent footing on Stewart 
Island, and some are confined thereto. 
Any one at all observant when climbing a high mountain 
cannot fail to notice at certain points a rather sudden change in 
the general aspect of the vegetation. Thus, for example, in ascend- 
ing Mount Egmont, the well-graded road, gradually rising, leads 
upward through the rain-forest, but at some 2,600 feet or so a tree- 
association of a different character is encountered, composed largely 
of the kamahi (Weinmannia racemosa), its gnarled, twisted branches 
far outspreading, the scene reminding one of some of Doré’s pictures. 
Passing one or other of the mountain houses, the path becomes 
steeper, the forest becomes lower, and then, almost on a sudden, 
it gives place to a subalpine scrub ; this in its turn—at, say, 4,000 
feet altitude—coming to a standstill and yielding place to what is 
there known as the “ moss,” but which in the language of this book 
may be called “‘ herb-field’ or “ tall tussock-grassland,” according 
to the combination of growth-forms. At a higher elevation still 
these formations are succeeded by a most open vegetation of a few 
lowly plants which can tolerate for their soil the loose scoria, and 
are exposed to the heavy winter snow. ‘This description does not 
apply, however, to the whole mountain, since on the west the 
‘““moss ”’ descends to a much lower altitude. 
In order to speak with precision of these vertical changes the 
following names may be given to the different rings of vegetation 
which girdle a mountain, such rings being termed “ belts.” These 
belts are three in number—the lowland, the montane, the sub- 
alpine—and perhaps their most important delimiting factor is the 
winter snowfall. 
For each botanical district the altitudinal limits of these belts 
must differ, and so, too, on every individual mountain according 
to the aspect of the slope. As soon as a height is reached upon 
a mountain where, in winter, snow has lain for some months at a 
time—say, 5,000 feet—certain plants, rare or wanting below, appear 
in abundance, and a new vegetation appears. Above this line is 
