''Marchantia'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

liverworts Liverworts are a group of non-vascular plant, non-vascular embryophyte, land plants forming the division Marchantiophyta (). They may also be referred to as hepatics. Like mosses and hornworts, they have a gametophyte-dominant life cycle, in wh ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Marchantiaceae Marchantiaceae is a family of liverworts in order Marchantiales. It contains a single genus ''Marchantia''. Genera in Marchantiaceae Until recently, three genera were included in the Marchantiaceae: * '' Bucegia'' Radian 1903 * ''Marchantia'' ...

and the

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Marchantiales Marchantiales is an order of thallose liverworts (also known as "complex thalloid liverworts") that includes species like '' Marchantia polymorpha'', a widespread plant often found beside rivers, and '' Lunularia cruciata'', a common and often t ...

. The genus was named by French botanist Jean Marchant after his father. The thallus of ''Marchantia'' shows differentiation into two layers: an upper photosynthetic layer with a well-defined upper epidermis with pores and a lower storage layer. The thallus features tiny cup-like structures called gemma cups, containing gemmae, small packets of tissue that are used for asexual reproduction. The combination of barrel-shaped pores and the circular shape of the gemma cups are diagnostic of the genus. Multicellular purple colored scales with single cell thickness and unicellular rhizoids are present on the ventral surface of the thallus.

Reproduction

''Marchantia'' can reproduce both sexually and asexually. Sexual reproduction involves sperm from

antheridia An antheridium is a haploid structure or organ producing and containing male gametes (called ''antherozoids'' or sperm). The plural form is antheridia, and a structure containing one or more antheridia is called an androecium. The androecium is al ...

on the male plant

fertilizing Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a zygote and initiate its development into a new individual organism or off ...

an ovum (egg cell) in the

archegonium An archegonium (: archegonia), from the Ancient Greek ''ἀρχή'' ("beginning") and ''γόνος'' ("offspring"), is a multicellular structure or organ of the gametophyte phase of certain plants, producing and containing the ovum or female gamet ...

of a female plant. The antheridia and archegonia are borne a top special

gametophore Gametophores are prominent structures in seedless plants on which the reproductive organs are borne. The word gametophore and ‘-phore’ (Greek Φορά, "to be carried"). In mosses, liverworts and ferns (Archegoniata), the gametophores suppor ...

stalks called antheridiophores and archegoniophores, respectively. These are borne on separate thalli and thus the plants are

dioicous Dioicy () is a sexual system in non-vascular plants where archegonia (female organs) and antheridia (male organs) are produced on separate plants in the gametophyte phase. It is one of the two main sexual systems in bryophytes, the other being ...

. Once fertilized, the ovum is called a

zygote A zygote (; , ) is a eukaryote, eukaryotic cell (biology), cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individ ...

and develops into a small

sporophyte A sporophyte () is one of the two alternation of generations, alternating multicellular organism, multicellular phases in the biological life cycle, life cycles of plants and algae. It is a diploid multicellular organism which produces asexual Spo ...

plant, which remains attached to the larger

gametophyte A gametophyte () is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the se ...

plant. The sporophyte produces

spore In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...

s which develop into free-living male and female gametophyte plants. Asexual reproduction occurs by means of gemmae, discoid clumps of cells which are genetically identical to the parent and contained in cup-like structures on the upper surface of the plant. These are dispersed when rain splashes into the cups and develop into new plants. Asexual reproduction can also occur when older parts of the plant die and the surviving newer branches develop into separate plants.

Species

Marchantia polymorpha ''Marchantia polymorpha'' is a species of large thalloid liverwort in the class Marchantiopsida. ''M. polymorpha'' is highly variable in appearance and contains several subspecies. This species is dioicous, having separate male and female plants. ...

'' (also as ''M. aquatica'') * ''

Marchantia quadrata ''Marchantia quadrata'' is a species of Marchantiophyta, liverwort, a simple non-flowering plant that grows as a flat, green, leaf-like structure (thallus) typically found on damp rocks and soil along stream banks in the Northern Hemisphere. The ...

'' (also as ''P. quadrata'') * '' Marchantia rubribarba'' * '' Marchantia solomonensis'' * '' Marchantia streimannii'' * '' Marchantia subgeminata'' * '' Marchantia vitiensis'' * '' Marchantia wallisii'' * '' Marchantia nepalensis''

References

External links

* * Marchantiales Marchantiales genera {{Bryophyte-stub