Moss (seed plants and pteridophytes), where the diploid sporophyte generation is dominant. Mosses are now classified on their own as the division Bryophyta. There are approximately 12,000 species. The main commercial significance of mosses is as the main constituent of peat (mostly the genus "Sphagnum"), although they are also used for decorative purposes, such as in gardens and in the florist trade. Traditional uses of mosses included as insulation and for the ability to absorb liquids up to 20 times their weight. Botanically, mosses are non-vascular plants in the land plant division Bryophyta. They are small (a few centimeters tall) herbaceous
Moss in cities. Examples would be "Rhytidiadelphus squarrosus", a garden weed in Vancouver and Seattle areas; "Bryum argenteum", the cosmopolitan sidewalk moss, and "Ceratodon purpureus", red roof moss, another cosmopolitan species. A few species are wholly aquatic, such as "Fontinalis antipyretica", common water moss; and others such as "Sphagnum" inhabit bogs, marshes and very slow-moving waterways. Such aquatic or semi-aquatic mosses can greatly exceed the normal range of lengths seen in terrestrial mosses. Individual plants or more long are common in "Sphagnum" species for example. Wherever they occur, mosses require liquid water for at least part of the year to complete