''Avicennia'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants t ...

s currently placed in the bear's breeches family,

Acanthaceae Acanthaceae is a family (the acanthus family) of dicotyledonous flowering plants containing almost 250 genera and about 2500 species. Most are tropical herbs, shrubs, or twining vines; some are epiphytes. Only a few species are distributed in tem ...

. It contains

mangrove A mangrove is a shrub or tree that grows in coastal saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evolution in severa ...

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...

s, which occur in the

intertidal zone The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species ...

s of

estuarine An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environmen ...

areas and are characterized by its "pencil roots", which are aerial roots. They are also commonly known as ''api api'', which in the

Malay language Malay (; ms, Bahasa Melayu, links=no, Jawi: , Rencong: ) is an Austronesian language that is an official language of Brunei, Indonesia, Malaysia, and Singapore, and that is also spoken in East Timor and parts of the Philippines an ...

means "fires", a reference to the fact that fireflies often congregate on these trees. Species of ''Avicennia'' occur worldwide south of the

Tropic of Cancer The Tropic of Cancer, which is also referred to as the Northern Tropic, is the most northerly circle of latitude on Earth at which the Sun can be directly overhead. This occurs on the June solstice, when the Northern Hemisphere is tilted towa ...

. The taxonomic placement of ''Avicennia'' is contentious. In some classifications, it has been placed in the family

Verbenaceae The Verbenaceae ( ), the verbena family or vervain family, is a family of mainly tropical flowering plants. It contains trees, shrubs, and herbs notable for heads, spikes, or clusters of small flowers, many of which have an aromatic smell. The ...

, but more recently has been placed by some botanists in the monogeneric family Avicenniaceae. Recent

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups ...

studies have suggested that ''Avicennia'' is derived from within

, and the genus is included in that family in the

Angiosperm Phylogeny Group The Angiosperm Phylogeny Group (APG) is an informal international group of systematic botanists who collaborate to establish a consensus on the taxonomy of flowering plants (angiosperms) that reflects new knowledge about plant relationships disc ...

system. Designation of species is made difficult by the great variations in form of ''

Avicennia marina ''Avicennia marina'', commonly known as grey mangrove or white mangrove, is a species of mangrove tree classified in the plant family Acanthaceae (formerly in the Verbenaceae or Avicenniaceae). As with other mangroves, it occurs in the inte ...

''. Between eight and 10 species are usually recognised, with ''A. marina'' further divided into a number of

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics ( morphology), but that can successfully interbreed. Not all specie ...

. The generic name honours Persian

physician A physician (American English), medical practitioner (Commonwealth English), medical doctor, or simply doctor, is a health professional who practices medicine, which is concerned with promoting, maintaining or restoring health through th ...

Avicenna Ibn Sina ( fa, ابن سینا; 980 – June 1037 CE), commonly known in the West as Avicenna (), was a Persian polymath who is regarded as one of the most significant physicians, astronomers, philosophers, and writers of the Islamic ...

(980-1037).

Description

Members of the genus are among the most salt-tolerant mangroves and are often the first to colonise new deposits of sediment. The sap is salty, and excess salt is secreted through the leaves. The spreading root system provides stability in shifting substrates. Vertical roots called

pneumatophore Aerial roots are roots above the ground. They are almost always adventitious. They are found in diverse plant species, including epiphytes such as orchids (''Orchidaceae''), tropical coastal swamp trees such as mangroves, banyan figs (''Fic ...

s project from the mud, thus the term "pencil roots". These are used in gas exchange as very little oxygen is available in the mud. The flowers are fragrant and rich in

nectar Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualist ...

, and are pollinated by insects. The embryos exhibit cryptovivipary, a process where they start to develop before the seed is shed, but do not break through the outside of the fruit capsule.

List of species

* '' Avicennia alba'' Blume * '' Avicennia balanophora'' Stapf & Moldenke * '' Avicennia bicolor'' Standl. * ''

Avicennia germinans ''Avicennia germinans'', the black mangrove, is a shrub or small tree growing up to 12 meters (39 feet) in the acanthus family, Acanthaceae. It grows in tropical and subtropical regions of the Americas, on both the Atlantic and Pacific Coasts, ...

'' (L.) L. * '' Avicennia integra'' N.C.Duke * ''

'' (Forssk.) Vierh. ** ''A. m.'' subsp. ''australasica'' (Walp.) J.Everett ** ''A. m.'' subsp. ''eucalyptifolia'' (Valeton) J.Everett ** ''A. m.'' subsp. ''marina'' ** ''A. m.'' var. ''rumphiana'' (Hallier f.) Bakh. * '' Avicennia officinalis'' L. * ''

Avicennia schaueriana ''Avicennia'' is a genus of flowering plants currently placed in the bear's breeches family, Acanthaceae. It contains mangrove trees, which occur in the intertidal zones of estuarine areas and are characterized by its "pencil roots", which are a ...

'' Stapf & Leechm. ex Moldenke * '' Avicennia tonduzii'' Moldenke

References

External links

* *
''Avicennia''
i

* {{Taxonbar, from=Q132645 Acanthaceae genera Taxa named by Carl Linnaeus Taxa named by Peter Forsskål Avicenna

Description

List of species

References

Further reading

External links