Bryophytes
Mosses
There are approximately 14,500 species of mosses. They are world-wide in distribution and can be found at sea level as well as the highest altitudes occupied by plants. Although they can occur in deserts or be submerged in water, most mosses occupy moist, shaded habitats. Mosses in partcular are sensitive to air polution. When air quality is poor, mosses are few or absent.Mosses are also mostly-terrestrial bryophytes of Kingdom Plantae. Like all members of division (phylum) Bryophyta, mosses are eukaryotic, have chlorophyll a and b as well as xanthophylls and carotenoid pigments for photosynthesis, store starch, and have pectin-cellulose walls.
Physical  Characteristics
Typicaly most bryophytes dont grow any taller than 20 centimeters, or eight inches tall. Moss gametophytes are either erect or extensively branched prostrate plants that consist of an axis (commonly called a stem) bearing spirally arranged leaf-like appendages (usually referred to as leaves); more often than not, they are anchored to the substratum by branched multicellular filaments called rhizoids.Although variable in shape, moss leaves usually consist of a single cell layer and are traversed by a midrib that is always more than one cell in thickness; it may extend from the base of the leaf to the tip or beyond, or may terminate some distance from the tip. The margins of the leaves are often toothed, the teeth pointed or rounded.   The thick green carpet of Moss you see on shady forest floors actually consist of Thousands of Tiny Moss Gametophytes. Each Gametophyte is attached to the soil by a root-like structures called RHIZOIDS.  Unlike roots, Rhizoids Do Not have Vascular tissue.  But Rhizoids do function like roots by Anchoring the Moss and by Absorbing Water and Inorganic Nutrients