Identifying which bryophyte is a moss and which is a leafy liverwort can be quite difficult and require some careful examination to tell the difference. Even then some species will fall outside the guidelines set out below.
Main Differences
Mosses
Liverwort
Polytrichum sp.
Mosses always have a stem and leaves, whereas not all liverworts do.
Monoclea sp.
Ptychomniaceae sp.
Liverwort leaves are arranged in one plane, those of mosses are arranged radially around the stem.
Liverwort leaf
Capsules and seta
The capsules and seta (Stalk) of mosses are green, brown or red depending on age. Where as those of liverworts are dark brown to black and oval in shape with a clear, transparent seta.
Capsules and seta
Moss Capsule
The capsules of a moss only open at one end in the form of a mouth, whereas the capsules of liverworts split open into any where from one to four valves, or by disintegrate.
Liverwort Capsule
Mosses leaves may have serrations, hairs, or a midrib that goes to the leaf tip, they do not have large indentations. Liverwort's leaves never have a midrib and often are lobed. Many liverworts have a third row of small leaves under the stem, but mosses rarely have these.