
This page is an introduction to Missouri's liverworts, with an overview of the group, their life cycle, and how to identify them.
Liverworts, like mosses, are land plants that do not have a vascular system. The lack of veinlike tubes to conduct moisture and nutrients throughout the plant limits them to a small size. Like ferns, they produce spores instead of seeds. Their form of reproduction usually requires them to be in wet or moist places.
Also like mosses, liverworts do not have true leaves, stems, and roots — at least not in the same sense as in vascular plants. But for simplicity’s sake, we tend to use these familiar terms instead of “leaflike structure,” “stemlike structure,” and “rhizoids.”
Liverworts fall into two groups based on their growth form:
- Thalloid or thallose liverworts look like green ribbons or scales that grow flat against a surface. This part of the plant is called the thallus. If the thallus branches, it does so in a Y-shaped pattern. There are no clearly defined stems or leaves.
- Leafy or scaly liverworts are much less familiar to people. They may resemble mosses or very tiny ferns. They have flattened stems with small, rounded, overlapping, leaflike scales in at least two rows; the stems often produce side branches.
The reproductive structures are usually important for identification. Those of the leafy liverworts are obscure, variable, and hard for an amateur botanist to see. Most of the thalloid liverworts, however, have obvious reproductive structures. See the Life Cycle section for more information.
In most cases, it’s easy to distinguish liverworts from mosses, but there are several key differences that can help you separate them:
- The leaves of leafy liverworts grow in two distinct rows, one row along each side of the stem, facing upward; there is often a third row, quite different and less noticeable, on the underside of the stem; these are called underleaves. Meanwhile, the leaves of mosses are attached all around the stem.
- The leaves of liverworts do not have a midrib, while the leaves of many mosses do have a midrib.
- The leaves of leafy liverworts are often lobed or notched at the tip, but while moss leaves may be toothed, they are never lobed or notched.
- Liverwort reproductive structures are short-lived, while the capsules of mosses may last for weeks or months.
- The rhizoids (rootlike structures) of liverworts are single-celled, while those of mosses have more than one cell (you’ll need a microscope to see this, however).
Separating the species of liverworts can be difficult even for botanists. You must note the shape, margins, and overlapping pattern of a liverwort's tiny leaves. Often, the plant's reproductive structures are required for making a conclusive ID. A microscope, or at least a hand lens, may be necessary, as well as a good grasp of some specialized terminology. Identification, for example, may use descriptions of the reproductive structures or even the spores. Examining spores requires a microscope.
Key parts of liverworts:
- Archegonia: the female reproductive structures (singular: archegonium)
- Antheridia: the male reproductive structures (singular: antheridium)
- Gemmae: specialized vegetative structures that can break off to become new plants; they are like tiny buds, leaves, or branches and often form inside a bowl-shaped structure called a gemmae cup (singular: gemma)
- Thallus: the main plant body of thallose liverworts, which grow in flat, usually green ribbons or sheets (plural: thalli)
Below are some common and widespread Missouri liverwort species.
Thallose liverworts
- Snakeskin liverwort (Conocephalum salebrosum) occurs on very moist soil or rocks, in rather shady areas, often in the splash zone of creeks. The thallus is in the form of large, flattened, irregular, overlapping straps. The surface is covered with air pores, giving it a bubbly appearance similar to snakeskin. The antheridia are fairly obscure and look like warty spots on the thallus. The archegonia are quite noticeable, resembling small mushrooms with conical heads (Conocephalum means conehead).
- Umbrella liverwort (Marchantia polymorpha) is similar to the above, but the thallus turns up at the edges; the netlike pattern on the upper surface is less deeply indented and less noticeable; it commonly has cuplike gemmae on the upper surface; the antheridia are stalked, with a flat, circular top with lobed or deeply scalloped edges. The archegonia, at first, look like small mushrooms, but at maturity they open to produce fingerlike projections radiating from the central stalk (looking like tiny palm trees). This species is fairly common in gardens and greenhouses.
- Hemispheric or purple-fringed liverwort (Reboulia hemisphaerica) occurs on soil or rocks. The thallus consists of many small, rounded lobes that are slightly cupped like shallow bowls. When the plant dries, these lobes may curl upward considerably. The margins of the thallus are somewhat rough and purplish. Unlike the two above, the surface of this liverwort is fairly smooth with very tiny air pores. The archegonium looks like a stalked umbrella with hairlike scales at the top of the stalk, under the cap. Unlike the above two, this species is monoecious (producing both male and female reproductive structures on the same plant).
- Floating crystalwort, or slender riccia (Riccia fluitans) floats in lakes, ponds, and streams, forming dense, tangled mats in shallow water. This is a thalloid liverwort, but it hardly resembles its relatively large, fleshy relatives. The thallus is long, slender, and flat. It branches profusely, with each branch ending in a notch. Occurs globally. Used in aquariums, especially in breeding tanks as cover for young fish. Nearly 20 species of Riccia have been recorded for Missouri, but this — one of the few floating species — is most common and widespread.
Leafy liverworts
- Frullanias, or scaleworts (Frullania spp.), are a large group of leafy liverworts, with 8 species in Missouri. Three, F. eboracensis, F. inflata, and F. riparia, are some of our most widely distributed liverworts, but they are overlooked by most people. Frullanias typically grow flat against the bark of trees and shrubs (F. riparia on rocks) or on dead trees, often in a delicate branching pattern. In many species, the overall spread may be only about 4 inches in diameter. Many frullanias are dark olive green, brownish, reddish, or purplish. The round leaves lie in two alternate rows, have no midribs, and typically overlap each other. Minute helmet-shaped leaf appendages can store water and help these tiny plants survive relatively dry situations.
- Variable-leaved crestwort (Chiloscyphus profundus; syn. Lophocolea heterophylla) is another common Missouri leafy liverwort. It is one of at least 9 species in its genus in Missouri. It has translucent, yellowish-green leaves growing on opposite sides of the stem. At the base, the older leaves have 2 lobes, while at the tip, the leaves may be smooth; in between, the leaves are merely notched. The pointed leaf tips give this liverwort a shaggy appearance overall. It is common on moist, rotting, barkless logs lying on the ground, usually near water. It looks mosslike, but mosses don’t have leaves in two rows like this.
- Porellas (Porella spp.) are rather large and vigorous for liverworts. Three species occur in Missouri: P. pinnata, P. platyphylla, and P. platyphylloidea. They are leafy and have numerous branches, giving them a crowded, matlike appearance. They grow flat against the trees or rocks they live on. The leaves are rounded, alternate, and arranged in two rows along the stem. Porellas are often brighter green than frullanias. In P. pinnata, the leaves are small and barely touch, while those of P. platyphylloidea are larger, more crowded, and overlap, giving it the gathered appearance of a raised curtain. As with crestworts, these mossy-looking liverworts have leaves in two rows, distinguishing them from true mosses.
Similar species: Several organisms can be mistaken for liverworts, especially since some liverworts might be mistaken for mosses! Here are some lookalikes.
- Missouri has 4 species of hornworts (division Anthocerotophyta) that might be mistaken for liverworts or mosses. Hornworts are named for their horn- or bullet-shaped sporophytes (reproductive structures). Except for the pointed, rather thickened sporophyte, the main body of the hornwort resembles liverworts or mosses. (These are not the same as the "hornwort" that commonly grows as a submerged plant in lakes and other aquatic habitats; that species, also called coon's tail, is a vascular plant.)
- Certain lichens have forms similar to liverworts, especially to some of the leafy liverworts. Lichens are composite organisms formed from specific combinations of fungi and algae. They have a drier texture than liverworts and lack the specific anatomy mentioned above.
Height: Most liverworts only cover an area a few inches wide, but some of the thallose liverworts can form large colonies on rocks along streams or in greenhouses.
Statewide. Different species can have different habitats and distributions. Their distribution in the state is poorly known, because certain parts of the state have been more thoroughly studied than others.
Habitat and Conservation
Liverworts, like mosses and ferns, usually occur in moist or wet, cool, shady places such as along stream banks, on the terraces above streams, and cool valleys on the north sides of slopes. They usually grow on a solid surface such as rocks or tree trunks, usually close to the ground. Certain species are associated with particular substrates and habitats.
Status
In Missouri, 40 species of liverworts are listed as species of conservation concern. A majority of them are listed as imperiled or critically imperiled, meaning they are especially vulnerable to extirpation from the state.
Taxonomically, liverworts (division Marchantiophyta), mosses (division Bryophyta), and hornworts (division Anthocerotophyta) are not closely related, but they are grouped together as nonvascular land plants and are often referred to informally as bryophytes. Although they share many characteristics, and all have ancient lineages and are considered “primitive” (ancestral) plants, they do not represent a single branch of a taxonomic tree, so their grouping is informal.
Previously, before DNA analysis showed they were not closely related, the three divisions were all considered as a single division, the Bryophyta. This is why they are still called bryophytes (with a little b) today.
Life Cycle
Liverworts have a two-part life cycle, each with a distinct plant structure. The part that is visible throughout the year — the main plant body, or thallus — is called the gametophyte (gamete-bearing plant). Gametophytes produce the sexual reproductive structures: sperm-bearing male structures called antheridia (singular antheridium) and egg-bearing female structures called archegonia (singular archegonium).
In most thallose liverworts, the antheridia and archegonia occur on separate plants. The archegonia are often stalked, arise from under the thallus, and have a lobed cap upon maturity. Depending on species or their stage of development, they may resemble small umbrellas, palm trees, or capped mushrooms. The antheridia may resemble a wart or they may have a tall, stalked appearance.
In leafy liverworts, the reproductive structures are tiny, obscure, variable, and hard for an amateur botanizer to see. Specialists use microscopes to examine them.
The sperm of liverworts are not enclosed in pollen grains; they must swim through water (usually rain water) to reach the archegonia. When a sperm unites with an egg, the resulting embryo develops into the second part of the life cycle, the sporophyte (spore-producing plant). The sporophyte develops within the archegonium and eventually pushes beyond it. The sporophyte has a capsule in which spores develop. When the sporophyte is mature, it sheds spores into the environment to develop into new gametophytes.
Asexual (vegetative) reproduction is very common in liverworts. As the gametophyte grows and branches, older parts die off and the branches continue as new plants. They can easily grow by cuttings, too. Floods can distribute fragments of liverworts downstream, creating new colonies.
The gemmae cups common in umbrella liverwort (Marchantia sp.) are another form of asexual reproduction. Gemmae can be thought of as tiny buds of the parent plant that separate to become new plants. On an umbrella liverwort, the gemmae look like tiny leaves inside the cup. When rain strikes the gemmae cups, it splashes the gemmae away to begin new plants.
Human Connections
Globally, some liverworts have been used medicinally. The common names “liverwort” and “hepatic” both refer to an antique belief that they could be used to treat liver ailments (think of hepatitis — inflammation of the liver). This belief was based on an idea called the Doctrine of Signatures, which started in Classical Greek and Roman days and continued in Europe into the 1600s. The idea was that God marked everything on earth with a sign (signature) that gives a hint to its purpose for humanity; therefore, if something resembled a lung, it could be used to heal lungs, and certain types of thallose liverworts, which supposedly look like a liver, could treat liver problems. In the 1700s, the development of the scientific method helped arrest this unsound reasoning.
Missouri’s liverworts and other bryophytes are understudied, mainly because they’re so small, and identifying them to species can be tedious.
Learning to identify these tiny plants takes time and practice, but it can be a fun challenge. Some people find great joy in “geeking out” over plant identification. The Internet provides a host of resources for anyone wishing to start learning more about these unusual plants.
Ecosystem Connections
Liverworts, mosses, and lichens gradually break down rocks and create soils, adding organic material and nutrients. Even in completely barren places covered only with rocks, they can be the first colonizers, changing the environment for other plants and animals to survive.
In some species, insects and springtails may help to distribute spores to new locations. Other animals such as shrews and mice may also move the spores around.
In spring, many birds hunt woodlands for soft, fibrous nesting materials, and liverworts and mosses are certainly among those used. Prothonotary warblers have been recorded using leafy liverworts in nest construction.
There are about 7,500–9,000 species of liverworts worldwide.












Mosses, liverworts, hornworts, and lichens seem rather similar, but these organisms are in very different groups. Mosses, liverworts, and hornworts are small, low plants usually found in damp habitats. Unlike more familiar plants, they lack veinlike structures and do not produce flowers or seeds — instead, they produce spores. Meanwhile, lichens are not plants at all: they are a collection of different fungi that have photosynthetic algae living within their tissues.