||Liverworts belong to a group of plants known as the Bryophytes which are usually green, usually small, and are amongst the simplest of land-dwelling plants (a few are aquatic). The name ‘liverwort’ derives from the Anglo-Saxon word ‘lifer’, meaning liver and ‘wyrt’, the 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.
||The bryophyte comprise the mosses, liverworts and hornworts. There are about 25,000 different species of bryophytes
||Liverworts have been found in fossils dating as far back as the Palaeozoic Era. They are believed to have shared a common ancestry with the green algae. There are approximately 8,500 species of liverworts. They are widely distributed, occurring from the arctic to the tropics. Although some grow in relatively dry places and a few are submerged aquatics, most liverworts occur in places where moisture is generally available, e.g., on damp soil or moist rotting logs, along shaded stream banks, on rocks in streams, or on wet rock outcroppings; a few even grow under saline conditions.
||Liverworts lack some of the complex structures seen in other types of plant — they do not produce flowers or seeds, and most have no internal means for transporting water or nutrients. There are two broad types of liverwort, separated on the basis of their general structure: leafy liverworts, and the thallose liverworts. The thallose gametophytes are flat, membranous forms with even, slightly wavy, lobed or leafy margins. There is a great diversity in the shape of liverwort leaves; they may be undivided, variously lobed or divided into hair-like segments, or they may be folded into two lobes of unequal size with the smaller lobe situated atop or below the larger.