The following curious observations on the habits of plants, were made by
General Walker, in his address to the Agricultural Society of St.
Helena, in February last:--"The functions of plants, as well as of
animals, depend upon the air in which they live. I have observed that
those of St. Helena, which have been brought from another hemisphere,
are very irregular in their annual progress; many of them, in the
development of their foliage, have adopted the law of nature peculiar to
the country into which they have been transplanted. Others, more
obstinate, remain faithful to their own habits, and continue to follow
the stated changes to which they had been accustomed. They all appear to
maintain a struggle either before they adopt the habits which belong to
the seasons of their new country, or decide on retaining their relations
with the old. In yielding to external circumstances, they appear to have
different tempers. This appearance of contention is often observed in
plants of the same species; they seem to hesitate and deliberate, ere
they adopt the mode of performing the functions of life. At length when
the decision is made, apparently not without pain and effort, we are at
a loss to discover an adequate cause. An oak, for instance, which loses
its leaves in a St. Helena winter of 68 degrees, scarcely experiences
the difference of temperature, which, reasoning by analogy, could cause
that change. It would have continued to maintain inflexibility, in its
original climate, its old habits, though exposed to far greater
irregularity and severity of climate. But though the law is obeyed by
many plants, it does not determine the periodical changes of the whole,
nor do they all submit to it with equal readiness and regularity. It
would add, I conceive, to the natural history of vegetation, and improve
our knowledge of the geography of plants, were the facts concerning
their habits and changes, under different temperatures, carefully
collected."
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