dressings were made, and the collection of sphagnum from the bogs in
which it nearly always grows was the task of many who could render no
other service.
The reproduction of sphagnum is not unlike that of ferns already
described. There is the same necessity of a film of water in which the
free swimming male can fertilize the female. But some other things about
their reproduction of young differ from ferns.
In the first place sphagnum is a nonvascular cryptogam, in that its
leaves have no veins or ducts in them and its minute stem is also
without those conducting passages that characterize all ferns, and the
flowering plants, which are considered the most highly developed of all
plant life. (See Chapter I for a discussion of this point, in the
section devoted to “Flowerless Plants.”)
In this moss, also, there are small branches, some of which bear only
the tiny leaves, but some bear leaves and the reproductive organs. The
female or _archegonia_ are much like those in the ferns, and the
_antheridia_ or male are also, as in the ferns, minute globular organs
in which are the male cells. The branches bearing males are greenish,
yellow, or even reddish, quite unlike the ashy gray foliage leaves which
give to sphagnum its characteristic ashy gray color. Unlike the ferns,
the male cells of sphagnum have only two tails, but they nevertheless
swim, tail first, to the female, when the time for fertilization comes.
The female branches are found mostly toward the upper end of the plant
and bear the archegonia at their extremities.
From what we know of the reproductive stages in the ferns it is now
obvious enough that in sphagnum moss, as we ordinarily see it, we have,
because it bears antheridia and archegonia, a quite different condition
from the ordinary spore-bearing leaves of ferns. For as yet spores have
not been developed on the moss. The mating of male and female cells,
directly on the plant, proves that in this “plant,” at least, our
ordinary notion of this moss is mostly confined to a stage in its life
history comparable in ferns to the production of archegonia and
antheridia on the fern prothallus. From this mating of the male and
female cells there results, as in the ferns, the production of a
spore-bearing structure. This consists of a spore case, matured for the
most part in the chamber occupied by the fertilized female cell, but
ultimately its cap is carried upward. Later on the spore case ruptures,
releasing the spores. As in the ferns, these germinate, forming a short
green protonema followed by a prothallus. From this a short leafy branch
develops, which completes the life cycle, as this is the young moss
plant.
Public-domain text, read in full here on John Shaqi.
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