THE STRUGGLE FOR EXISTENCE 205 
would not be sufficient to prohibit forest growth is 
abundantly shown by the luxuriant vegetation on 
Ruapehu’s western slopes, which forms a striking 
contrast with the Onetapu desert on its eastern side, 
where reduced rainfall, together with unfavourable 
soil conditions, has resulted in an almost total absence 
of plant life. Central Otago and the Canterbury 
Plains no doubt owe their steppe character to the same 
cause. On the Canterbury Plains, too, as well as in 
Central Otago, the rainfall is, generally speaking, insuffi- 
cient to permit of forest growth. Before reaching 
Canterbury, the available moisture in the north-west 
winds is precipitated on the western slopes of the 
Southern Alps, so that these winds, after crossing the 
Alps, instead of bringing a supply of moisture, actually 
parch the soil and vegetation over which they blow. Add 
to this the fact that on the east there is no mountain 
range or other permanent cause for precipitation of the 
moisture brought by the prevailing north-east winds, 
and we account at once for the striking contrast between 
the almost tropical Iuxuriance of the Westland forests 
and the essentially steppe character of much of the 
Canterbury Plains. On the Taupo plateau, as well 
as in Canterbury and Otago, the soil is not 
clothed with a close sward, as is the case in 
European grass land, but is covered with scattered 
bunches or tufts of grass belonging chiefly to native 
species of poa and fescue. Among these are the 
smaller tufts of danthonia, the native oat-grass. The 
tufted nature of these grasses gives to the steppes the 
name of tussock-land. 
In many. parts of New Zealand, pastures of 
the European type have been formed by the 
industry of man. Here we find perennial rye, cocks- 
foot, sheep’s fescue, and several clovers, as well as a 
ereat variety of noxious weeds whose seeds have been 
accidentally introduced from abroad. 
