Bauhinia variegata L.

Bauhinia variegata is a small to medium-sized deciduous tree with a short bole and spreading crown, attaining a height of up to 15 m and diameter of 50 cm. In dry forests, the size is much smaller. The bark is light brownish grey, smooth to slightly fissured and scaly. Inner bark is pinkish, fibrous and bitter. The twigs are slender, zigzag; when young, light green, slightly hairy, and angled, becoming brownish grey. Leaves have minute stipules 1-2 mm, early caducous; petiole puberulous to glabrous, 3-4 cm; lamina broadly ovate to circular, often broader than long, 6-16 cm diameter; 11-13 nerved; tips of lobes broadly rounded, base cordate; upper surface glabrous, lower glaucous but glabrous when fully grown. Flower clusters (racemes) are unbranched at ends of twigs. The few flowers have short, stout stalks and a stalklike, green, narrow basal tube (hypanthium). The light green, fairly hairy calyx forms a pointed 5-angled bud and splits open on 1 side, remaining attached; petals 5, slightly unequal, wavy margined and narrowed to the base; 5 curved stamens; very slender, stalked, curved pistil, with narrow, green, 1-celled ovary, style and dotlike stigma. Pods dehiscent, strap-shaped, obliquely striate, 20-30 by 2-25 cm; long, hard, flat with 10-15 seeds in each; seeds brown, flat, nearly circular with coriaceus testa. The generic name commemorates the Bauhin brothers Jean (1541-1613) and Gaspard (1560-1624), Swiss botanists. The two lobes of the leaf exemplify the two brothers. The specific name refers to the variegation of the flowers.

In its natural habitat in India, the tree is deciduous, remaining leafless from Jan-Feb to April with leaf fall in Nov-Dec. Flowering occurs when the plant is leafless. Tree starts flowering at a very early age of 2-3 years. The seeds disperse from the pods and germinate on sites with favourable light and moisture conditions, while in unfavourable niches the radicle dries up or is destroyed by birds.

Capable of growing on a wide range of soils from gravelly, shallow, rocky soil on hill slopes to sandy loam and loamy soil in the valley.

B. variegata is a plant of tropical and subtropical climates with hot, dry summers and mild winters. It demands plenty of light and requires good drainage. Severe frost kills the leaves of seedlings and saplings, but they recover during summer. The tree is fairly resistant to drought but susceptible to fires.

B. variegata reproduces itself naturally from seeds, which are dispersed before the monsoon in India, and germinate with the start of the rains. Regeneration is sometimes plentiful in fresh soil deposits on landslips. Natural regeneration is scanty because birds and insects destroy most of the seed lying exposed on the ground. The tree yields viable seed from an early age. Pods are collected before they dehisce in May and June and are dried in the sun to release seeds. Artificial propagation is through direct sowing and stump planting. Both methods are quite successful and considered better than planting out 1-year-old seedlings. Branch cuttings root only with difficulty. Soaking seeds in water at room temperature for 24 hours improves germination to about 95%.

Direct-sown lines need to be thinned to about 1 m spacing at the end of 1st year. In regular plantations, the trees should be kept adequately thinned as they grow. The tree coppices well and can stand heavy lopping fairly well. Because B. variegata has been cultivated sporadically, generally in and around cultivation and habitations, or in mixed forests or avenue plantations, no systematic block plantations have been established. It has therefore been treated according to the objectives in view, so applicable management practices have not been evolved.

The larvae of several insects feed on the plant. Adult nymphs of Psylla simlae feed on sap of leaves and young twigs. Leaves and flowers infested by nymphs shrivel and fall.

Seed storage behaviour is orthodox; no loss in viability in hermetic storage at room temperature for at least 2 years; viability maintained for more than 3 years in hermetic storage at room temperature with 13 ± 2% mc. Seeds stored in tins give germination rates of up to 95% after a few months of storage. There are 2 800-3 500 seeds/kg.

Ornamental: The showy fragrant, pink, purple or white flowers make the tree attractive for an ornamental and for avenue plantings.

Food: The leaves, flowers and flower buds are eaten as vegetables. Fodder: Leaves make good fodder and are greedily eaten by sheep, goats and cattle. The average annual fodder yield per tree is 15-20 kg of dry matter. Apiculture: It blooms in early winter and spring in India. The buds being consumed as a vegetable, bees have little chance of taking proper advantage of the bloom. Fuel: One of the main uses of B. variegata is as fuel; calorific value is 4 800 kcal/kg. Fibre: The bark yields a suitable fibre. Timber: The wood is brown and moderately hard and used for agricultural implements. Gum or resin: The tree yields a gum. Tannin or dyestuff: The bark produces tannins, used in various shades of brown. Lipids: The seeds are made up of 20% endocarp and 80% kernel. They yield 16.5% of a pale yellow, fatty oil on extraction with petroleum ether but only 6.1% in an hydraulic press. Medicine: The bark decoction is used for diarrhoea control, as an astringent alternative and for treating scrofula, skin diseases and ulcers.