Liverwort

The Marchantiophyta are a division of <a href="/facts/Non-vascular_plant/z1LbfESm">non-vascular</a> <a href="/facts/Embryophyte/8pzYKGvv">land plants</a> commonly referred to as hepatics or liverworts. Like <a href="/facts/Mosses/YF8Rbf8y">mosses</a> and <a href="/facts/Hornworts/NLDvbs9G">hornworts</a>, they have a <a href="/facts/Gametophyte/g1zag3Su">gametophyte</a>-dominant life cycle, in which cells of the plant carry only a single set of genetic information. The division name was derived from the genus name <a href="/facts/Marchantia/VDMIbQIw">Marchantia</a>, named by French botanist <a href="/facts/Jean_Marchant/YNIEjbeK">Jean Marchant</a> after his father.
It is estimated that there are about 9000 species of liverworts. Some of the more familiar species grow as a flattened leafless <a href="/facts/Thallus/4FbF7wmC">thallus</a>, but most species are leafy with a form very much like a flattened <a href="/facts/Moss/YF8Rbf8y">moss</a>. Leafy species can be distinguished from the apparently similar mosses on the basis of a number of features, including their single-celled <a href="/facts/Rhizoid/dDgxHqSu">rhizoids</a>. Leafy liverworts also differ from most (but not all) mosses in that their leaves never have a <a href="/facts/Costa_(botany)/RjjcIGWp">costa</a> (present in many mosses) and may bear marginal <a href="/facts/Cilia_(botany)/RjjcIGWp">cilia</a> (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. Liverworts are distinguished from mosses in having unique <a href="/facts/Complex_oil_bodies/fhkHVgzs">complex oil bodies</a> of high refractive index.
Liverworts are typically small, usually from 2 to 20 mm (0.079 to 0.787 in) wide with individual plants less than 10 cm (3.9 in) long, and are therefore often overlooked. However, certain species may cover large patches of ground, rocks, trees or any other reasonably firm substrate on which they occur. They are distributed globally in almost every available habitat, most often in humid locations although there are desert and Arctic species as well. Some species can be a nuisance in shady greenhouses or a weed in gardens.

Liverwort open-in-new

Liverwort