Uncaria gambir (Hunter) Roxb.

A liana often cultivated as a straggling shrub, with square young stems bearing horizontal branches with recurved hooks (modified peduncles of inflorescences). Leaves opposite, subcoriaceous, and entire, ovate to (broadly) elliptic, (6-)9-12(-15) cm x (3.5-)5-7(-8) cm, rounded to subcordate at base, acute at apex, glabrous, with 5-6 pairs of lateral nerves, raised below and with hairy domatia. Flowers in heads on horizontal plagiotropic branches; heads (3.5-)4-5 cm in diameter (across corollas), receptable densely hairy, interfloral bracteoles absent; pedicel up to 3 mm long, hypanthium 1-2 mm in diameter, densely yellow-brown hary; calyx 3-4.5 mm long, with 5 trigonal, 1-2 mm long lobes, exterior densely yellow-brown sericeous, quickly falling off from the heads; stamens 5, adnate to the corolla; ovary inferior, style exserted 5-7 mm, stigma obovoid to clavate, ca. 2 mm. Fruiting head (50-)60-80 mm in diameter, fruitlets (capsules) 14-18 mm long, sparsely pubescent and crowned by the calyx, many seeded; fruit stalks up to 20 mm long. Seeds very tiny, silvery grey. Uncaria gambir is frequently confused with other related species, particularly Uncaria callophylla Blume ex Korth., Uncaria acida (Hunter) Roxb. and Uncaria elliptica R. Br. Ex G. Don (synonym: Uncaria dasyoneura Korth.). These species have been reported to have been incidentally used in gambier production. Recently a plant from Sumatra with denser foliage, called 'Uncaria payakumbuh', has been mentioned as a gambier source. The catechin content of this plant is somewhat less than that of 'true' gambir

Gambier has no special soil requirements, but it is usually cultivated on soils with a rich humus layer, or containing much clay.

Wild gambier is most commonly found in secondary forest. It does not occur in dry regions or at higher altitudes. The plant does not tolerate waterlogging.

Gambier is cultivated in Peninsular Malaysia and Indonesia (Sumatra, Java, Bali, Kalimantan, Moluccas). Plants which are probably truly wild have been collected in Sumatra and Borneo.

Propagation is usually by seeds. The very small and light seeds rapidly lose their viability. Seeds are usually sown in seed-beds. To achieve a uniform dispersal, the seeds are often blown into seed-beds. On slopes, the vertical walls of terraces are sometimes used as seed-beds and the seeds are blown to the walls. Horizontal seed-beds need protection from sun and rain. Seeds take about 2 weeks to germinate. Gambier may be propagated vegetatively by cuttings, by layering, or by grafting. Vegetative methods of propagation usually result in an advanced first harvest. However, these plants are recorded to contain less tannin at harvest.

Plantation: Usually seedlings are transplanted into the field 2-7 months after sowing, depending on the region. Planting distance is 2 m x 3 m or 3 m x 3 m. The seedlings are usually planted in the edge of a hole, and the hole is not filled with soil. Husbandry: No special practices are necessary except weeding during the first year. Fertilizers are usually not applied. Although gambier is a natural climber, no support is needed for cultivated plants when the crop is managed properly.

In smallholdings, gambier is usually free from serious diseases and pests. However, in large monocultures plagues of caterpillars and beetles have been reported. A mite causes monstrous inflorescences and also attacks the leaves.

The seeds are very light; 1 kg contains about 25 000 000 seeds.

Intercropping: Gambier can be intercropped as a cash crop in rubber and oil palm plantations.

Tannin or dyestuff: Tanning leather is one of its major uses. And one of its minor uses are as a dye in the traditional batik industry and for dyeing silk black. Other products: As a stimulant chewed with betel nut (Areca catechu L.), lime and the leaf of Piper betle L.. As a clearing agent for beer, and as a remover of scale from boilers. Medicine: The leaves are also used fresh for medicinal purposes. As a medicinal plant, gambier is used as an astringent. An infusion of fresh leaves given against diarrhoea, dysentry, and as a gargle for sore throats. Gambier is also used as a styptic, and against inflamed gums. It is applied externally in lotions for burns and in a paste for scurf. External application against sciatica and lumbago is reported from Borneo. Gum or resin: The resinous substance extracted from the leaves and young branches of gambier is crystalized and traded in small cubes or blocks.