131 
ON THE STRUGGLE FOR EXISTENCE AMONGST 
PLANTS. 
By J. D. HOOKER, M.D., F.R.S. 
T HE quaint dictum, u Plants do not grow where they like 
best, hut where other plants will let them,” which is credited 
to the late eminent horticulturalist, Dean Herbert, of Manches- 
ter, expresses a truth not yet half appreciated by botanists. It 
is a protest against the prevalent belief, that circumstances 
of climate and soil are the omnipotent regulators of the dis- 
tribution of vegetables, and that all other considerations are 
comparatively powerless. The dean’s crude axiom has lately 
found a philosophical exposition and expression, in Mr. Darwin’s 
more celebrated doctrine of the ct Struggle for life, and preserva- 
tion thereby of the favoured races,” and if to it we add that 
great naturalist’s more fruitful discovery, of the necessity for 
insect and other foreign agencies in ensuring fertility, and 
hence perpetuating the species, we shall find that the powers 
of climate and soil are reduced to comparatively very narrow 
limits. Before proceeding to show what are the causes that 
do materially limit the distribution of species, it may be well 
to inquire how far the hard-pressed soil and climate theory 
really helps us to a practical understanding of one or two great 
questions that fall under our daily observation ; of these, the 
following are the most prominent. 
That very similar soils and climates, in different geographical 
areas, are not inhabited, naturally, either by like species, or like 
genera ; — that very different soils and climates will produce 
almost equally abundant crops of the same cultivated plants ; 
— and that in the same soil and climate, many hundreds, nay, 
thousands of species, from other very different soils and. climates, 
may be grown, and propagated, for an indefinite number of 
successive generations. 
Of the first , of these statements, the examples embrace some 
of the best known facts in geographical botany ; as, for example, 
that the Flora of Europe differs wholl} T from that of temperate 
North America, South Africa, Australia, and temperate South 
America, and all these from one another. And that neither soil 
nor climate is the cause of this difference, is illustrated by the 
