| Avicennia | |
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| Avicennia germinans | |
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Avicennioideae
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| Genus: | Avicennia |
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Avicennia is a genusofflowering plants currently placed in the bear's breeches family, Acanthaceae. It contains mangrove trees, which occur in the intertidal zonesofestuarine areas and are characterized by aerial roots. It is commonly known as api api which in the Malay language means "fires", a reference to the fact that fireflies often congregate on these trees.[2] Species of Avicennia occur worldwide south of the Tropic of Cancer.
The taxonomic placement of Avicennia is contentious. In some classifications it has been placed in the family Verbenaceae, but more recently has been placed by some botanists in the monogeneric family Avicenniaceae. Recent phylogenetic studies have suggested that Avicennia is derived from within Acanthaceae, and the genus is included in that family in the Angiosperm Phylogeny Group system.
Designation of species is made difficult by the great variations in form of Avicennia marina. Between eight and ten species are usually recognised, with Avicennia marina further divided into a number of subspecies.
The generic name honours Persian physician Avicenna (980-1037).[3]
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. There are vertical roots called pneumatophores projecting from the mud. These are used in gas exchange as there is very little oxygen available in the mud. The flowers are fragrant and rich in nectar 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.[4]
