OTHER INDIGENOUS INDUCED ASSOCIATIONS. 151 
specially abundant. In spring there is plenty of the hemlock storks- 
bill (Erodium cicutarium). In some places the Australian comb 
wheat-grass (Agropyron pectinatum) has gained a secure footing. 
The most important alien of all is the winged thistle (Carduus pyeno- 
cephalus), which, thistle though it be, is credited with supplying a 
large amount of nutritious food. Burning, and overstocking both 
with sheep and rabbits, have there been elsewhere in the mountain 
areas of the South Island, but there the climate has been wetter ; 
it was the extremely dry situation—the driest in New Zealand— 
which has turned for the time being so much of Central Otago into 
a man-made desert. Irrigation, however, will in part remedy this 
state of affairs, and the higher belts of the mountains, where the 
rain is more plenteous, are in no danger of becoming “ depleted 
areas.” 
During the survey for the Midland Railway considerable areas 
on and near the summit of Arthur’s Pass were burnt, the associations 
destroyed being in some cases subalpine scrub, and in other cases 
subalpine forest of tree-daisies, the pauhau-tea (Libocedrus Bidwilli), 
and the mountain-neinei (Dracophyllum Tvraversii). According to 
the aspect, the soil, and the original association, so differ the new 
associations, but all agree in the fact that they are composed of 
New Zealand plants. In some places the burning has led to almost 
a pure association of the mountain-flax (Phormium Colensoi) being 
established ; in other places a scrub of the subalpine koromiko 
(Veronica subalpina) dominates. The interesting feature of the case 
is that the dominant plants of the regenerating vegetation are 
frequently not the dominant ones of the original plant-covering. 
Draining raupo (Typha angustifolia) swamp leads in a very short 
time to the drained ground being covered thickly with densely grow- 
ing bushes of New Zealand flax (Phormium tenax). Such drained 
swamp, although wet enough in winter, often becomes exceedingly 
dry in summer, and so, for much of the year, is a swamp no longer. 
Whoever first made this discovery of turning raupo swamp into 
dense Phormium brought millions of pounds sterling to New 
Zealand. Bonuses were offered again and again by various Govern- 
ments to reward him who should devise better means of preparing 
the commercial fibre, but no reward was offered for what lay at the 
root of the whole matter—the establishment of a perennial supply 
of raw material. 
