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.
Hornworts are a group of bryophytes constituting the division Anthocerotophyta. The common name refers to the elongated horn-like structure, which is the sporophyte. As in mosses and liverworts, the flattened, green plant body of a hornwort is the gametophyte plant.
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.
Jungermanniales is the largest order of liverworts. They are distinctive among the liverworts for having thin leaf-like flaps on either side of the stem. Most other liverworts are thalloid, with no leaves.
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.
Lejeuneaceae is the largest family of liverworts. Most of its members are epiphytes found in the tropics, while others can be found in temperate regions.
Jungermanniopsida is the largest of three classes within the division Marchantiophyta (liverworts).
Buxbaumia is a genus of twelve species of moss (Bryophyta). It was first named in 1742 by Albrecht von Haller and later brought into modern botanical nomenclature in 1801 by Johann Hedwig to commemorate Johann Christian Buxbaum, a German physician and botanist who discovered the moss in 1712 at the mouth of the Volga River. The moss is microscopic for most of its existence, and plants are noticeable only after they begin to produce their reproductive structures. The asymmetrical spore capsule has a distinctive shape and structure, some features of which appear to be transitional from those in primitive mosses to most modern mosses.
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.
Treubiaceae is a family of liverworts in the order Treubiales. Species are large and leafy, and were previously classified among the Metzgeriales.
Haplomitriopsida is a newly recognized 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.
Blasiales is an order of liverworts with a single living family and two species. The order has traditionally been classified among the Metzgeriales, but molecular cladistics suggests a placement at the base of the Marchantiopsida.
Apotreubia is a genus of liverworts in the family Treubiaceae. There are four species, including: Apotreubia nana, which is found in subalpine New Guinea, and Apotreubia pusilla, which has a disjunct distribution between eastern Asia and British Columbia.
Pleurozia is the only genus of liverworts in the family Pleuroziaceae, which is now classified in its own order Pleuroziales, but was previously included in a broader circumscription of the Jungermanniales. The genus includes twelve species, and as a whole is both physically distinctive and widely distributed.
Ptilidium is a genus of liverwort, and is the only genus in family Ptilidiaceae. It includes only three species: Ptilidium californicum, Ptilidium ciliare, and Ptilidium pulcherrimum. The genus is distributed throughout the arctic and subarctic, with disjunct populations in New Zealand and Tierra del Fuego. Molecular analysis suggests that the genus has few close relatives and diverged from other leafy liverworts early in their evolution.
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.
Treubia scapanioides is a species of liverwort in the family Treubiaceae. Until recently, the genus was placed in the order Metzgeriales. There are only 6 species in the genus Treubia. Five are native to Australasia but T. scapanioides is known only from Chile.
Fossombroniales is an order of liverworts.
Petalophyllum, or petalwort, is a genus of liverworts in the order Fossombroniales.
Ricciocarpos natans is the only species in the genus Ricciocarpos, a genus of liverworts in the family Ricciaceae. It was formerly listed in 1759 as a species of Riccia by Linnaeus, but then assigned to a new genus of its own in 1829 by August Carl Joseph Corda.
