| Avicennia | |
|---|---|
 | |
| Avicennia germinans | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Asterids |
| Order: | Lamiales |
| Family: | Acanthaceae |
| Subfamily: | Avicennioideae Miers |
| Genus: | Avicennia L. (1753)[1] |
| Species | |
See text | |
| Synonyms[2] | |
| |
Avicennia is agenus offlowering plants currently placed in thebear's breeches family,Acanthaceae. It containsmangrovetrees, which occur in theintertidal zones ofestuarine areas and are characterized by its "pencil roots", which areaerial roots. They are also commonly known asapi api, which in theMalay language means "fires", a reference to the fact thatfireflies often congregate on these trees.[3] Species ofAvicennia occur worldwide south of theTropic of Cancer.
The taxonomic placement ofAvicennia is contentious. In some classifications, it has been placed in the familyVerbenaceae, but more recently has been placed by some botanists in the monogeneric familyAvicenniaceae. Recentphylogenetic studies have suggested thatAvicennia is derived from withinAcanthaceae, and the genus is included in that family in theAngiosperm Phylogeny Group system.
Designation of species is made difficult by the great variations in form ofAvicennia marina. Between eight and 10 species are usually recognised, withA. marina further divided into a number ofsubspecies.
The generic name honoursPersianphysicianAvicenna (980–1037).[4]
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 shiftingsubstrates. Vertical roots calledpneumatophores 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 innectar, 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.[5]
Eight species are currently accepted:[2]
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Media related toAvicennia at Wikimedia Commons
Data related toAvicennia at Wikispecies