Changes

*''Visiania elastica'' (Roxb.) Gasp. (1844), *''Urostigma elasticum'' (Roxb.) Miq. (1847).

*India rubber tree (En). *Arbre à caoutchouc (Fr)

*Malaysia: bunoh seteroh (Kelantan). *Burma (Myanmar): bedi

*Vietnam: cây [dd]ađa.

The latex from the bark of the stem and larger branches of ''F. elastica'' contains rubber, which can be used for all applications of natural rubber, such as tyres, rubber components for cars and machines and consumer products such as footwear, sport goods, toys and gloves. Centuries ago, the latex was used to line baskets of split rattan, to make them watertight. In the late 19th and early 20th Centuries plantations were established, mainly in Sumatra, Java and Peninsular Malaysia, but India rubber was soon eclipsed by para rubber ( ''Hevea brasiliensis'' (Willd. ex Juss.) Müll.Arg. ''F. elastica'' is presently a very common ornamental or shade tree which is also cultivated as a foliage pot plant.

The latex has a specific gravity of 0.96-1.00 and contains (10-)30-40(-58)% rubber with relatively large rubber particles in the latex compared with other latexes. The resin content of the latex varies widely, with estimates ranging from 3% to 25%. Latex from older trees contains less resin, as does the older tissue in a plant: the latex from the top of a plant 2.3 m tall contained 25% resin while latex collected from its base contained 18% resin. The resin content of the latex of trees grown at higher altitudes is higher: latex from trees grown at 45 m altitude contained 3% resin and that from trees growing at 750 m altitude 22% resin. The rubber made from ''F. elastica'' contains 4-20% resin, which hardens over time and decreases the rubber's elasticity. The rubber has relatively short chains of polyisoprenes of low molecular weight: 78 000. It is soluble in cajeput oil ( ''Melaleuca cajuputi'' Powell). The rubber is hypoallergenic to individuals allergic to the proteins found in ''Hevea brasiliensis'' rubber products. The latex showed toxicity to the juveniles of the nematode ''Meloidogyne javanica'' .

*A large, evergreen, strangling tree, up to 55 m tall with abundant aerial roots from the trunk and the main branches which do not thicken to form "pillar roots", bark surface smooth, inner bark pale pink producing white latex; twigs glabrous. *Leaves arranged spirally, simple; stipules lanceolate and flaccid, connate into an accrescent, narrow, membranous, bright red, long-acuminate cap, 7-35 cm long, largest on lower branches; petiole 2-5 cm long, red when young; blade oblong to elliptical, usually 10-15 cm × 4-7.5 cm, up to 40 cm × 22 cm on lower branches and in saplings, dark green, glabrous, leathery, base cuneate to almost rounded, margin entire, apex shortly acuminate, up to 25 mm long on lower branches, primary vein red when young, with 13-26 pairs of well-developed parallel secondary veins, with intramarginal veins, upper leaf surface with abundant cystoliths, stomata deeply sunken. *Inflorescence a fig (syconium), axillary, in pairs, sometimes solitary; peduncle 1-3 mm long, finely puberulous; basal bracts 3, 3 mm long, falling off very early with the stipules and leaving an annular scar; flowers .*Flowers unisexual; male flowers dispersed, with short pedicel, tepals (3-)4, free, eventually spreading, stamen 1, anther 4-celled, dehiscing longitudinally; gall flowers sessile or with short pedicel; female flowers sessile, tepals 4, free, ovary unilocular, emergent, with a single ovule, style single, subterminal, stigma simple, subcapitate. *Infructescence a fig, shortly ellipsoidal, 9-12 mm × 8-9 mm, yellow when ripe; individual fruit a drupelet. *Seedling with epigeal germination; cotyledons emergent, cotyledons and first pair of leaves appear simultaneously; hypocotyl elongated; first pair of leaves with coarsely-crenate margin with fine punctuations which disappear in older leaves, all leaves arranged spirally.

The symbiotic relation of ''Ficus'' spp. with specialized wasps is well-known. Figs can only be pollinated by female agaonid wasps ( ''Hymenoptera'' , ''Chalcidoidea'' , ''Agaonidae'' ). These wasps are highly species-specific; the fig-wasp associated with ''F. elastica'' is ''Blastophaga clavigera'' , known from India. In ''F. elastica'' the wasps arrive when female flowers are receptive. They enter the fig via the osteole, a bract-covered apical pore. Once inside they pollinate the female flowers and deposit their eggs in the ovaries. As style length varies greatly within these figs and because the wasp can only reach the ovary of short-styled flowers, only some of the flowers obtain an egg, while in others the seed develops. Male and female wasps emerge after a few weeks, and mate within the fig. The females then emerge from the fig and, in so doing pick up pollen from the newly mature anthers of male flowers. Figs on a single tree mature at the same time, while different trees of the same species flower out of synchrony, thus inducing cross-pollination. ''F. elastica'' seedlings develop root nodules containing 95% water, which act as a water reservoir. This most probably helps the seedlings to survive the initial epiphytic phase. During this phase the plant sends down thin aerial roots which only thicken after they have reached the ground. In Java, ''F. elastica'' flowers throughout the year. In Luzon, the Philippines, it flowers in January-March. Young specimens in Java are reported to be epiphytic. The root system of ''F. elastica'' is shallow and dense, making mixed plantation or intercropping systems impossible. Roots may anastomose over a distance of 40 m, as reported for India.

A common disease of ''F. elastica'' pot plants is anthracnose caused by the fungus ''Glomerella cingulata'' . Anthracnose develops pale rose-coloured pustules, usually scattered along the veins. Any wound or breaking of leaves or accumulation of water on the leaves for considerable periods will favour infection. Twig blight and canker caused by ''Fusarium lateritium'' are other diseases of ''F. elastica'' pot plants.

As the latex of ''F. elastica'' is not harvested at present, the harvesting techniques described here are those used a century ago. The latex of wild as well as planted trees is collected by tapping the bark, generally only of the stem and larger branches, though root bark may also be tapped. It is best to harvest when the air humidity is high, as drier conditions cause the latex to coagulate too fast and rain reduces the rubber content of the exudate. Traditionally the bark was cut with a knife or small axe, later incisions were made with a gouge to better control the depth of cutting and to limit the wounding of the cambium. In the bark the laticifers are found closest to the cambium in a fibrous tissue which is difficult to cut. If the incision is not deep enough, the tissue containing most laticifers is not tapped and yield is low. A deep incision damages the cambium and hence influences the vitality of the tree. A V-shaped gouge can also be used to make horizontal incisions up to 5 cm wide and some 20 cm long, the length never exceeding half the circumference of the tree. These cuts are about 40 cm apart and on opposite sides of the tree. A herringbone system has also been applied, in which a central vertical channel transports the latex from grooves made at an angle of 45°with 45° with the vertical to a container driven into the bark of the tree. Inside the inclined grooves the fibres are punctured or cut at intervals of 2-3 cm, to tap the laticifers closest to the cambium. This, however, also punctures or cuts the cambium layer. An advantage of the herringbone system is that the latex is collected as a fluid and is of better quality than the "scrap" collected from the horizontal incisions or from underneath the tree. The latex drips from the horizontal incisions for about 2-3 minutes and is collected on a mat or on leaves placed underneath the tree. The coagulated latex is collected 2-3 days later; when stripped off the incision a milky residue oozes from the wound, but this liquid contains no rubber. A well-developed planted tree can be tapped after 6-7 years, but with increasing age (and circumference of the tree) when the first tapping is done, both yield as well as rubber content of the latex increase.