TAYLOR: DOMINANCY IN NATURE. 
29 
the struggle for supremacy resulting in the expulsion of a species 
from any region is very keen and necessarily very prolonged. 
But if dominant European plants be naturally or artificially placed 
upon unoccupied or virgin land or in some weak and primitive 
region where the native organisms are comparatively low in the scale 
of life and the difference of dominancy therefore great, so that the 
competition they encounter is less effective and deadly, the stronger 
species rapidly multiply and speedily over-run the country of which 
they take almost complete possession, quickly expelling the native 
organisms. In this way the thistles of various kinds have over-run 
immense tracts of land in South America, and now form dense and 
lofty thickets : while in the United States, New Zealand and other 
weak countries the European weeds are rapidly dominating and 
driving off or destroying the native vegetation. 
The actuality of this struggle and its inevitable results are well 
shown by a neglected garden, where the rapid growth of weeds 
speedily results in the crowding out and destruction of the cultivated 
plants, many of which can perfectly well endure our climate, but 
cannot compete with our native plants, and, therefore, cannot 
become naturalized, for it cannot be too strongly emphasized that 
the struggle with other plants, etc., is far more important than the 
influence of soil or climate in determining distribution. 
The effects of the struggle for the possession of the most desirable 
ground is seen by the fact that modern groups tend to monopolize 
them, while the most primitive species are found to have sought 
refuge within the dim recesses of extensive forests, in arid or desert 
regions, or in marshy tracts and other unfavourable stations, where 
the species driven to such shelters have undergone the changes 
necessitated by the modes of life they have by stress of circumstances 
been compelled to adopt. 
The dominating tendency is shown by the aggregation and 
formation of great forests or extensive tracts of more or less specific 
uniformity, a feature characteristic of distinctly dominant forms of 
life, not only in plants, but in all other departments of Nature, and 
one unfailing indication of decreasing dominating power is found in 
the increasing diversity of the woodland trees, and other forms of 
life as we proceed eastward from the European region. 
The distribution of the p]delweiss {Leontopodiam alphium) also 
clearly displays the greater severity of the competitive struggle in 
Europe as there that species is now quite restricted to the mountain 
regions, while in Asia, where the flora is more primitive and the 
competition less severe, it is a common lowland meadow flower. 
The richness and diversity of specific life in any region or district 
is one of the most striking evidences of the weakness of its organic 
life, for such regions form a refuge or sanctuary for those numerous 
forms of life that have been worsted in their contest for superiority 
with the stronger species. 
