THE STRUGGLE FOR EXISTENCE 213 
from watching the new vegetation that springs up in 
a region devastated by a bush fire. First cat’s-ear, 
certain grasses, thistles and other annual weeds appear. 
These, as a rule, are followed by quick-growing shrubs 
and small trees such as the manuka, wineberry and 
rangiora. But, as time goes on, true forest trees 
begin to make their appearance, small at first, but 
cradually raising themselves above, and dominating 
the surrounding vegetation. In the raupo swamp may 
be observed a process more gradual and natural, for 
here there is no need for the aid of fire. As the raupo 
dies down year after year, the shallower parts of the 
swamp finally become more or less solid, so that rushes, 
sedges, and plants of that nature are able to gain 
a footing. These pave the way for buttercups, penny- 
royal, and coarse grasses, till the whole swamp may 
be gradually converted into a wet meadow. 
On many of the lava streams of New Zealand it is 
possible to observe the first. beginnings of vegetation, 
as well as the different stages of the various successions 
that appear. Rangitoto, a volcanic cone rising from 
the sea in the neighbourhood of Auckland, is admirably 
suited for such investigation. It would appear from 
the extent of voleanic action, that the original 
flora must, in the various eruptions, like that of 
Krakatoa, have been utterly destroyed. Here the 
first signs of vegetation visible to the eye are the 
orey lichens that cover the bare rock. These by their 
decomposition form a humus which gives a footing to 
the mosses. The latter form mats that catch the dust 
consisting of powder formed from the decomposed 
rock and tiny particles of organic material broken from 
neighbouring lichens and mosses. When these eollect- 
ine grounds have a sufficient supply of humus and 
decomposed rock, a drought resisting fern, the creeping 
polypody, makes its appearance, and, forming a 
deeper and more open mat, collects the wind-drift more 
