A LITTLE BACKGROUND ON MOSSES/AQUATIC MOSSES Photo of- Fissiden sp. Mosses belong to the group of plants call Bryophytes which never produce flowers or seeds. They have a long history of evolution compared to flowering plants, with fossil record dated back 440 million years ago in the Silurian period. Most of the mosses are small, non-vascular, land plants, but some may be as large as 35cm tall and some are semi-aquatic. The mosses share a unique life cycle in having a first generation of dominant gametophyte. The gametophyte forms the green leafy structure we ordinarily associate with moss. Mosses are essentially land plants, and they depend on a film of water for the male cell (spermatozoid) to be transported to the female cell, both which are produced on the gametophyte. When conditions are right, the next generation, the sporophyte or spore-bearing structure is grown. The sporophyte is typically a capsule growing on the end of a stalk called the seta. The sporophyte has no chlorophyl and it grows parasitically on its gametophyte mother. The sporophyte dries out and releases spores that grow into a new generation of gametophytes, if they germinate. In general, when we are talking about mosses, we are generally referring to the gametophyte generation of the mosses life cycle. Mosses do not have veins to transport water and food, instead, all parts of the plant are used to absord water and nutrients. Hence, mosses are found mostly at places where there are a consistent supply of water. Mosses have rhizoids instead of roots, which are branched threads. While the rhizoids can absorb water, they are mainly used to anchor the plant.
Posted on: Sun, 02 Nov 2014 12:13:01 +0000
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