Mosses are small, non-vascular flowerless plants in the taxonomic division Bryophytasensu stricto. Bryophyta may also refer to the parent group bryophytes, which comprise liverworts, mosses, and hornworts. Mosses typically form dense green clumps or mats, often in damp or shady locations. The individual plants are usually composed of simple leaves that are generally only one cell thick, attached to a stem that may be branched or unbranched and has only a limited role in conducting water and nutrients. Although some species have conducting tissues, these are generally poorly developed and structurally different from similar tissue found in vascular plants. Mosses do not have seeds and after fertilisation develop sporophytes with unbranched stalks topped with single capsules containing spores. They are typically 0.2–10 cm (0.1–3.9 in) tall, though some species are much larger. Dawsonia, the tallest moss in the world, can grow to 50 cm (20 in) in height. There are approximately 12,000 species.
The Marchantiophyta are a division of non-vascular land plants commonly referred to as hepatics or liverworts. Like mosses and hornworts, they have a gametophyte-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 Marchantia, named by French botanist Jean Marchant after his father.
Marchantiales is an order of thallose liverworts that includes species like Marchantia polymorpha, a widespread plant often found beside rivers, and Lunularia cruciata, a common and often troublesome weed in moist, temperate gardens and greenhouses.
Lunularia is a genus of liverworts whose only species is Lunularia cruciata, the crescent-cup liverwort. Lunularia is either the only genus in the order Lunulariales, or may be placed in the order Marchantiales. The name, from Latin luna, moon, refers to the moon-shaped gemma cups.
Metzgeriales is an order of liverworts. The group is sometimes called the simple thalloid liverworts: "thalloid" because the members lack structures resembling stems or leaves, and "simple" because their tissues are thin and relatively undifferentiated. All species in the order have a small gametophyte stage and a smaller, relatively short-lived, spore-bearing stage. Although these plants are almost entirely restricted to regions with high humidity or readily available moisture, the group as a whole is widely distributed, and occurs on every continent except Antarctica.
Conocephalum is a genus of complex thalloid liverworts in the order Marchantiales and is the only extant genus in the family Conocephalaceae. Some species of Conocephalum are assigned to the Conocephalum conicum complex, which includes several cryptic species. Conocephalum species are large liverworts with distinct patterns on the upper thallus, giving the appearance of snakeskin. The species Conocephalum conicum is named for its cone-shaped reproductive structures, called archegoniophores. Common names include snakeskin liverwort, great scented liverwort and cat-tongue liverwort.
Monoicy is a sexual system in haploid plants where both sperm and eggs are produced on the same gametophyte, in contrast with dioicy, where each gametophyte produces only sperm or eggs but never both. Both monoicous and dioicous gametophytes produce gametes in gametangia by mitosis rather than meiosis, so that sperm and eggs are genetically identical with their parent gametophyte.
Cavicularia densa is the only species in the liverwort genus Cavicularia. The species was first described in 1897 by Franz Stephani, and is endemic to Japan, where it grows on fine moist soil.
Haplomitriopsida is a class of liverworts comprising fifteen species in three genera. Recent cladistic analyses of nuclear, mitochondrial, and plastid gene sequences place this monophyletic group as the basal sister group to all other liverworts. The group thus provides a unique insight into the early evolution of liverworts in particular and of land plants in general.
Riella is a genus in the liverwort family Riellaceae, and includes about eighteen species. Plants in the genus are small and grow submerged in shallow temporary pools. Although the genus is widely distributed in the Northern Hemisphere, locating populations is often difficult. Its occurrence is sporadic and local, and the tiny plants are ephemeral. The ornamented spores remain viable for several years, allowing the plants to survive annual drying of their habitat. The plants are easily grown in laboratory cultures.
Conocephalum conicum, also known as the great scented liverwort or snakeskin liverwort, is a liverwort species in the genus Conocephalum. C. conicum is part of the Conocephalum conicum complex, which includes several cryptic species. The name C. conicum refers to the cone-shaped archegoniophore, which bear sporangia.
Petalophyllum ralfsii, the petalwort, is a liverwort of the order Fossombroniales. It is a small green bryophyte that occurs in the Mediterranean region as far east as Turkey, and along the Atlantic coast of Europe as far as northwest Scotland. It grows primarily on moist sand dunes.
Trichocolea tomentella is a species of liverwort belonging to the family Trichocoleaceae. It forms loose, pale green to yellowish-white mats and is characterised by its highly divided leaves that give it a feathery or fuzzy appearance. The species has a wide distribution across temperate regions of the Northern Hemisphere, particularly in oceanic and suboceanic areas, occurring in Europe, Asia, North Africa, and eastern North America. It typically grows in moist, shaded locations, especially near springs and streams in deciduous and coniferous forests. While capable of sexual reproduction, with male and female structures on separate plants, it reproduces predominantly through vegetative means via branching and fragmentation. The species shows considerable morphological variation between populations but maintains stable taxonomic characteristics in its cell structure. Though it can form extensive pure patches and effectively compete with other bryophytes in suitable habitats, T. tomentella faces threats from habitat destruction, particularly through logging and drainage of its preferred moist forest habitats.
Porella platyphylla is a species of liverwort belonging to the family Porellaceae. It has a Holarctic distribution, occurring across Eurasia and North America, where it typically grows on tree bark and rocks in areas with adequate rainfall. The species is most common in regions receiving at least 600 millimetres of annual precipitation. The species forms part of a complex taxonomic group that includes several closely related species and hybrids, with populations showing distinct genetic differences between continents despite their morphological similarity.
Conocephalum supradecompositum is a species of thalloid liverwort in the genus Conocephalum, of the order Marchantiales and the family Conocephalaceae. C. supradecompositum has a distribution that is mainly restricted to China and Japan. C. supradecompositum has very distinct chemical composition from the species Conocephalumconicum.
The oil bodies of liverworts, occasionally dubbed complex oil bodies for distinction, are unique organelles exclusive to the Marchantiophyta. They are markedly different from the oil bodies found in other land plants and algae in that they are membrane-bound, and not associated with food storage. The organelles are variable and present in an estimated 90% of liverwort species, often proving taxonomically relevant. As a whole, the formation and function of the organelles are poorly understood. Complex oil bodies are recognized as sites of isoprenoid biosynthesis and essential oil accumulation, and have been implicated with anti-herbivory, desiccation tolerance, and photo-protection.
Endogemma is a monotypic genus of liverworts belonging to the family Endogemmataceae and subclass of Jungermanniineae.
Petalophyllum preissii, the lettuce liverwort, is a species of liverwort that is the type species of the family Petalophyllaceae. It is found in Australia and New Zealand, and is at risk of extinction in both countries.
Asterella palmeri, also known as Palmer's asterella, is a species of liverwort native to southwestern North America that can be found growing between roughly 30° and 40° north latitude. The plant is found in the U.S. state of California as far north as Redding, and in the Mexican state of Baja California as far south as Punta Baja, as well as in the northwestern corner of U.S. state of New Mexico. According to California bryologists William T. Doyle and Raymond E. Stotler, Palmer's asterella is typically found around chaparral, conifers, and in oak woodland in "exposed to lightly shaded summer-dry soil; usually on gentle to steep slopes." This liverwort is usually found below 950 metres (3,120 ft) elevation, but in the southern Sierra Nevada can be found at up to 1,250 metres (4,100 ft) above sea level.
