Pics: (click for larger image)
The name "liverwort" derives from the Anglo-Saxon word "lifer, meaning liver and "wyrt", the Anglo-Saxon word for plant. During the 16th century, it was commonly applied to the genus Marchantia, a flat, branching, ribbon-shaped plant the margins of which were claimed to resemble the lobes of a liver.
It is estimated that there are about 9000 species of liverworts. Some of the more familiar species grow as a flattened leafless thallus, but most species are leafy with a form very much like a flattened moss. Leafy species can be distinguished from the apparently similar mosses on the basis of a number of features, including their single-celled rhizoids. Leafy liverworts also differ from most (but not all) mosses in that their leaves never have a costa (present in many mosses) and may bear marginal cilia (very rare in mosses). Other differences are not universal for all mosses and liverworts, but the occurrence of leaves arranged in three ranks, the presence of deep lobes or segmented leaves, or a lack of clearly differentiated stem and leaves all point to the plant being a liverwort.
