154 NEW ZEALAND PLANTS. 
in diameter, while others were extremely slender. Thousands of 
manuka seedlings sprang up along with those of the gum; and it 
must not be forgotten that manuka, far more than most of the indi- 
genous plants, can reproduce itself again and again after burning, and 
can exclude almost all other vegetation. But in this case the great 
rapidity of growth gave the gums the victory, and eight years ago 
only a little manuka remained near the margin of this remarkable 
and quite natural forest-growth. Nor is the above only interesting 
biologically : it is equally important from the point of view of cheap 
afforestation of unproductive areas covered with manuka thicket. 
With regard to sweetbrier (Rosa rubiginosa) on the one hand, 
and blackberry (Rubus fruticosus) on the other, both form dense 
thickets, but their distribution is strictly limited by climatic con- 
ditions, the former demanding a dry and the latter a rain-forest 
climate. 
The foxglove (Digitalis purpurea) has increased its area of dis- 
tribution greatly of recent years, In those parts of Nelson and 
Marlborough, for example, possessing a forest-climate acres and 
acres of ground where southern-beech forest has been burnt are 
occupied closely by this plant, which with its purple and white 
flowers makes a wonderful display, as on the slopes bounding the 
Rai Valley. In places at present the strife is between the foxglove 
and the bracken-fern, but the latter is pretty sure to be the victor. 
Every introduced species has what may be called its likes and 
dislikes with regard to its dwelling-place ; so, too, for that matter, 
as has been seen in the previous chapters, have the indigenous species. 
A few examples may be of interest. 
The horehound (Marrumbium vulgare) is virtually confined to 
places on low tussock-grassland where sheep camp, where it forms 
a pure adventitious association. The goat’s-rue (Galega officinalis) 
was observed for the first time in New Zealand about fifteen years 
ago near Woodville, on the bank of the Manawatu River. At the 
present time it may be seen in great quantity almost anywhere on 
the banks of that river, and not there alone but on the adjacent 
ground, though only so far as the river has deposited silt in time 
of flood. The mullein (Verbascwm Thapsus) grows on the loose 
stony ground of river-terraces or hillsides, on river-beds, and on the 
‘ depleted areas’ of Central Otago and Marlborough. The viper’s- 
bugloss (Hchium vulgare), the Australian piripiri (Acaena ovina), 
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