''Radula'' is a genus of

liverwort 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 ...

, and is the only genus in family Radulaceae. It is a leafy liverwort. The appearance of the plants are as a scaly, green surface on the trunk of a tree, log or rock in a sheltered, moist out-door environment. The leaves are rounded, overlapping and consist of two unequal lobes. The smaller lobe is folded beneath the larger one. The oldest fossil species is ''Radula cretacea'' from the Cenomanian aged

Burmese amber Burmese amber, also known as Burmite or Kachin amber, is amber from the Hukawng Valley in northern Myanmar. The amber is dated to around 100 million years ago, during the latest Albian to earliest Cenomanian ages of the mid-Cretaceous period. ...

of Myanmar, belonging to the

subgenus In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed betw ...

'' Odontoradula.'' Molecular evidence suggests that the genus arose during the

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...

, around 227.8 Ma, and the

crown group In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. ...

began to diversify during the

Early Jurassic The Early Jurassic Epoch (in chronostratigraphy corresponding to the Lower Jurassic Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-Jurassic extinction event, 201.3 Ma ...

, around 176.3 Ma. Species include: * ''

Radula boninensis The radula (, ; plural radulae or radulas) is an anatomical structure used by Mollusca, molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before ...

'' * ''

Radula carringtonii The radula (, ; plural radulae or radulas) is an anatomical structure used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the foo ...

'' J.B.Jack * ''

Radula cavifolia The radula (, ; plural radulae or radulas) is an anatomical structure used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food ...

'' * ''

Radula complanata The radula (, ; plural radulae or radulas) is an anatomical structure used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food ...

'' * ''

Radula deflexilobula The radula (, ; plural radulae or radulas) is an anatomical structure used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food ...

'' Promma, L.N.Zhang et R.L.Zhu * ''

Radula demissa ''Radula demissa'' is a species of liverwort. Distribution The species is found in Australia and New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the ...

'' M.A.M.Renner, 2013 * ''

Radula javanica The radula (, ; plural radulae or radulas) is an anatomical structure used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food ...

'' * ''

Radula jonesii ''Radula jonesii'' is a species of liverwort in the family Radulaceae. It is known from a few locations on Madeira and one location on Tenerife. The populations are small and vulnerable. This liverwort forms dark green to olive green mats on ro ...

'' Bouman, Dirkse & Yamada * ''

Radula kojana The radula (, ; plural radulae or radulas) is an anatomical structure used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food ...

'' * ''

Radula laxiramea The radula (, ; plural radulae or radulas) is an anatomical structure used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food ...

'' * ''

Radula marginata ''Radula marginata'', or Wairuakohu, is a species of plant in the genus ''Radula'', a genus of liverworts. It is endemic to New Zealand. It has been found to contain cannabinoids. Cannabinoids Users smoking the plant have experienced differe ...

'' * ''

Radula obtusiloba The radula (, ; plural radulae or radulas) is an anatomical structure used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food ...

'' * ''

Radula perrottetii ''Radula perrottetii'' is a species of plant in genus ''Radula'', a genus of liverworts. It is endemic in Japan. It contains the small molecule perrottetinene a cannabinoid Cannabinoids () are several structural classes of compounds found in t ...

'' * ''

Radula visianica ''Radula visianica'' is a species of liverwort in the Radulaceae family. It is European Alps endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other ...

'' C. Massal.

References

External links

* * * Porellales Porellales genera {{bryophyte-stub