Leaves and mature fruit (inclosing crypto-viviparous propagule) of A. integra
Mature fruit with pericarp covering of A. marina
2 species in Australia, one with 3 varieties
Avicennia L. (1753) is the sole genus in the exclusively pantropic mangrove family Avicenniaceae Endl., once grouped within the family Verbenaceae. This small but widespread and distinct mangrove family is characterised by anomalous secondary thickening, leaf anatomy, characteristic pollen, incipient vivipary and seedling morphology.
Avicennia consists of eight species worldwide including: five in the Indo-West Pacific - A. alba, A. integra, A. marina, A. officinalis L. and A. rumphiana Hallier f.; and three others in the Atlantic East Pacific. Two species, A. integra and A. marina occur in Australia. Avicennia are generally considered pioneers of mangrove forests. They occupy a diversity of habitats within the tidal range and across salinity extremes of tropical and subtropical sheltered areas. In tropical regions, this often includes a select group of co-inhabitors, like Rhizophora.
In subtropical and temperate tidal habitats, Avicennia often dominant as trees or shrubs. A special cold-tolerant variety grows at latitudes as high as 38° 45’ S in southern Australia, making this the most widely distributed of any mangrove genus.
Derivation of Genus Name
Named in honour of the famous Arabian physician and scientist, abu-Ali al-Husayn ibn-Sina, known as Avicenna (980-1037) - his Qanun remained the standard medical textbook on plants for 500 years after his death.
Avicennia occur throughout most tropical-subtropical regions of the world. Of the two species found in Australia, A. marina is ubiquitous and widespread while A. integra is rare and restricted to around 16 estuaries in the Northern Territory. The latter species has the distinction of being the only endemic mangrove species in Australia.
Key to Australia's Avicennia species
Two Avicennia species are recognised in Australia’s mangroves and occur in most sheltered areas along the mainland coast. They are distinguished by flower size, margins of calyx lobes, style shape, fruit shape, leaf apex shape and bark colour.