(F H iii
ii
V J
oval form, having four elastic filaments, thickened at the ends,
coiled around them. These, when the spore has become
ripe, unroll; and their elasticity, no doubt, contributes to
burst the case in which the spores are contained, as well as to
assist in the dispersion of these minute reproductive bodies.
They are, indeed, so irritable, that a change of temperature
or moisture, such as that produced by breathing on the
spores, is sufficient to produce this forcible uncoiling. The
spores themselves are very interesting microscopic objects ;
indeed, it is only under a high magnifying power that their
nature can be examined.
The germination of the spores has been made the subject
of experiment by several inquirers, whose observations
have been published. Agardh states, that from three to
fourteen days after the spores are sown, they send down a
thread-like transparent root somewhat thickened at the end,
and protrude a confervoid, cylindrical, obtuse, articulated,
torulose thread, which is either two-lobed or simple at the
apex. Some days after this, several branches are produced,
and become agglutinated together, forming a body resembling
a bundle of confervoid threads, each of which pushes
out its own root. Bischoff finds these confervoid threads
go on growing and combining until a considerable cellular
mass is formed. Then, this mode of development ceases,
and a young bud is formed, which produces the stem of an
Equisetum, at once completely organized, with its air-cells,
its central cavity, and its sheaths, the first of which is formed
before the elongation of the stem, out of the original cellular
matter.
To watch the minute atoms thus springing into life, developing
by degrees their tiny stems, and gaining strength
and bulk day by day until they reach maturity, could hardly
fail, one would think, to lead a sensitive mind to pure and
wholesome thought, and to call up the contemplation of
the wise and beneficent plans and the all-sufficiency of the
Creator, by whose ordaining providence life interminably renewable
had thus been made to spring from the dust-like
spore, as well as to produce a just appreciation of the uncertainty
and insufficiency of human agency; for though
man may plant and water, yet it is God alone that giveth
the increase.
i. I