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Moreover , the extraordinary variety in New Zealand of Natural 
Orders in proportion to the genera, and of genera in proportion 
to the species 1 speaks in favour of its having formerly been con- 
tiguous to larger bodies of land; while, on the other hand, the 
peculiarity of the species is an evident proof that this contiguity 
must have ceased to exist for a very long time past. It would 
become the duty of geology to prove that former contiguity, and 
by it the original soil of the mother flora. But here the difficulties 
are crowding together, and it is only to daring hypotheses that 
we can take refuge. The hypothesis of only one continent , sunk in 
the vast gulf, would not suffice; it would be necessary to premise 
three or four such continents. First an extensive main land with 
a rough continental climate. At that time , the antarctic genera 
which now-a-days are found upon the higher ranges , covered the 
whole extent of the land. When the sea with its milder breezes took 
the place of the land, the frightened children of the South Pole 
fled into the cooler mountain regions, and a new flora took pos- 
session of the lower landscape. Simultaneously or in alternating 
succession with essential climatic changes, New Zealand was then 
united with Chili, with the tropical islands of the South Sea, and 
with Australia by means of a continental bridge over which the 
plants could conveniently immigrate, receiving representatives from 
1 The number of Natural Orders is large in proportion to the genera; being as 
92 to 282, that is, about one to three, while the genera are to the species as 282 
to 730, each genus having on the average only two and a half species; whence it 
follows that there are, on the average but 8 species to each Natural Order. In Great- 
Britain each order counts 14 species; but the probable proportion of the species to 
the known Orders throughout the globe is as 350 to 1. The extraordinary variety 
of forms upon a limited insular space would be a very singular occurrence, if it were 
not substantiated as a fact in Nature itself, that one and the same area is the more 
productive of life, the greater the variety of forms in that life, since homogeneous 
bodies mutually tend to destroy, but heterogeneous bodies to sustain each other. 
This variety of forms, moreover, is quite regularly distributed upon New Zealand, 
and the differences in the vegetation of different districts are fewer by far, than 
the extraordinary variety of the structure of the ground would lead one to infer. 
Considering these circumstances and the additional one, that, very many of the 
Natural Orders cannot be recognised by the flower alone, by fruit alone or by 
habit or foliage, it may safely be said, that the New Zealand Flora, is, for its 
extent, much the most difficult on the globe to a beginner. 
