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You may
know that the ferns are a fairly primitive group of plants that were on earth a million years before the dinosaurs, having only a rudimentary vascular system and never having
developed flowers or seeds. In the right conditions, propagation by spore seems
to be an extremely effective means of reproduction, provided a few basic needs
are met.
In
flowering plants, a seed produces a plant which grows to maturity, produces
male, female or dioecious (male and female) flowers, pollinates and/or is pollinated, and the pollinated flower then produces seed to complete the cycle.
In ferns and other spore-producing plants (mosses, liverworts and tree ferns),
spore germinates and produces a gametophyte consisting of a single simple leaf called a prothallis. It is the
gametophytes which do the reproducing in these plants: the male organs of the gametophytes
release sperm, which, dependent upon the presence of a film of water on the
surface of the growing area (certainly one of the reasons why these plants are
usually restricted to moist, humid environments), travels between gametophytes
and fertilizes the female organs. At this point a new plant is produced which is
immediately more
recognizable as a fern, and which will reach maturity and
itself produce spore to complete the cycle. Colonies of gametophytes can apparently continue to
produce ferns for some time, so in cultivation plantlets can be removed and the
colony left to continue to reproduce, which is a pretty good
deal.
A. peruvianum gametophytes, in a somewhat
underwhelming photo. Image © In Situ Plants.
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With my
little A. peruvianums, the first part of the cycle is complete (although
perhaps it's difficult to call a part of any cycle the first part). What
remains to be seen is whether germination can be achieved: the outermost layer
of the garden material does not have the constant film of water that the
habitat of A. peruvianum does, but I am attempting to keep the area as moist as
possible in an effort to assist germination. Here's hoping for a favourable
outcome; the little gametophytes certainly do add an interesting element to the
garden, though, at any rate.
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