Bruguiera rumphii Blume

A moderate-sized, evergreen tree up to 36 m tall; bole 40-65 cm in diameter, buttressed and with kneed pneumatophores. Bark grey to almost black, roughly fissured, usually with large corky lenticels on buttresses and base of stem. Branching mostly sympodial. Leaves decussately opposite, simple and entire, coriaceous, elliptic to oblong, 8.5-22 cm x 5-7(-9) cm; base cuneate, rarely obtuse, apex acute; nerves 9-10 pairs; petiole 2-4.5 cm long, often reddish. Flowers solitary, 3-3.5 cm long, generally nodding, with 1-2.5 cm long, often reddish. Flowers solitary, 3-3.5 cm long, generally nodding, with 1-2.5 cm long pedicels, which are bright red on the outside curve; calyx red to pink-red, lobes (10-)12-14(-16), tube usually ribbed at the upper part; petals 13-15 mm long, 2-lobed with acute lobes, each with 3-4 long bristles, outer margins fringed with white silky hairs especially at the base; stamens 8-11 mm long, with linear anthers, embraced by the petals; ovary inferior, style about 15 mm long with filiform stigma. Fruit a campanulate berry enclosed by the calyx tube, 2-2.5 cm long, 1-celled and 1(-2)-seeded. Hypocotyl cigar-shaped, slightly angular, with a blunt narrowed apex, perforating the apex of the fruit and falling with it, 15-25 cm x 1.5-2 cm. This species belongs to AubrÚville's model of tree-architecture. It is one of the largest trees of the mangrove, and probably the longest living.

In Cambodia and Vietnam it flowers abundantly in the rainy season from May to November.

Black mangrove is characteristics of the landward side of mangroves, usually growing on somewhat dry, well-aerated soil. It often ascends tidal parts of rivers. Sometimes it forms pure stands, but often it is associated with Rhizophora species, especially R. apiculata Blume, but also Ceriops tagal (Perr.) C.B. Robinson and Xylocarpum moluccensis (Lamk) M. Roemer. It marks the climax vegetation of littoral forests (mangroves), before the transition to land forest. It is a shade tolerant species, and able to establish itself even in pure stands of Rhizophora L. The regeneration after felling is usually scant or even absent. Black mangrove has proved to be able to grow, flower, fruit and even regenerate in artificial fresh water swamps, as in the botanical garden in Bogor (Indonesia). In fact, it is sensitive to high salt concentrations, dying soon above 3% NaCl.

Seedlings can be collected either from the trees or from the ground. They are equally viable. They can be planted in a nursery, and transferred to the field 3-4 months later, spacing 3 m x 1 m. This is how the tree is propagated in Cilacap (Indonesia). Seedlings develop best where the tidal range is only about 0.35 m and the salinity is 1-2.5%. Seedlings can remain alive, floating in the water, for 5-6 months, which possibly explains the large area of distribution. The natural and artificial regeneration has never been extensively investigated.

The liana Derris trifoliata Lour. is a common weed associated with this species. Usually this weed is controlled manually, because herbicides may affect the fauna living around the trees. Some authors have proposed a 10-year rotation but in Malaysia a 20 year rotation has long been practised.

Pests: Seedlings may be attacked by mangrove crabs like Scylla serrata, Sesarma meinerti, and S. smithii. In Cilacap (Indonesia), plantations have suffered from caterpillars of the genus Acanthopsyche, but these pests have been controlled succesfully by using Dimercon 100 at concentrations of 0.1%.

Reclamation: This species might be succesfully used for reafforestation in areas where mangroves have been destroyed.

Tannin or dyestuff: The bark is suitable for tanning leather and fishing nets as it contains up to 35% tanning substance in air-dry bark. A phlobaphene colouring matter from the bark is sometimes used as a dye in Malaysia and Vietnam for black or dark-brown colour, but this use is considered as minor. The tannin imparts a reddish colour to leather, and is often mixed with other tannins in the tanning industry. Chopped bark may be used directly in the tannery. The tannin can be extracted by boiling the bark in large vessels and evaporating down to a solid. Fibre: The wood can be used for the paper industry, but the paper is of poor quality. Timber: The timber is used less so for piles, house posts, rafters, fishing stakes,and telegraph poles. Poles have a life of about 10 years. Medicine: The bark is used as an astringent medicine against diarrhoea and sometimes malaria. The fruits are suitable as an eye medicine. Food: The leaves and peeled hypocotyls are eaten in times of scarcity in the Moluccas after having been soaked in water and boiled. In Jakarta (Indonesia), formerly the starchy central part of the hypocotyl was treated with sugar for food. Fuel: The timber is used for firewood and charcoal. Other products: The fruits are sometimes used as an astringent in betel quid when nothing better is available.