Local names:
English (purple bauhinia,orchid tree,camel's foot tree,butterfly tree,geranium tree), Hindi (kota,raktakanchan,khairwal,karar,kanchan), Malay (tapak kuda), Nepali (tanki), Spanish (pie de cabra), Thai (sieowaan,sieo dok daeng), Trade name (kachan,karar,k
Bauhinia purpurea is a small to medium-sized deciduous fast-growing shrub or tree with a round, symmetrical, moderate dense crown to 10 m tall, young branches becoming glabrous or nearly so (glabrescent). In dry forests, the size is much smaller. The bark is pale grey brown, fairly smooth to slightly fissured and scaly. The twigs are slender, light green, slightly hairy, and angled, becoming brownish grey. The heart-wood is brown, hard and durable. Leaves simple, alternate, base rounded to shallow-cordate, up to 12 cm x 12 cm, deeply 2-lobed at apex up to 1/3-1/2, ca. 7-12 cm long, and equally wide, margin entire and the surfaces smooth and glabrous, and 9- or 11-nerved at base, the apex lobes rounded or obtuse to subacute, minute stipules 1-2 mm long, petioles puberulous to glabrous, 2.5-3.5 cm long; leaf blades 4.5-11 cm long. Inflorescence a 6-10-flowered raceme in terminal panicles; flowers numerous, hypanthium, turbinate, purple to nearly white or at least purple-marked, the flower buds clavate (club-shaped), velvety, ca 3-4 cm long prior to anthesis; fertile stamens 3 or 4, the anthers ca 6 mm long, versatile; ovary superior; corolla of 5 narrow petals and constricted at base, oblanceolate, 3-5cm long, claws 5-10mm long, the banner purple-striate, ca 7 mm wide; calyx tubular, erupted by corolla along one side when flower fully expanding; calyx split into 2 valves with 5 teeth. In fall, before the leaves drop, Orchid-Tree is festooned with many showy and delightfully fragrant, five-inch-wide blossoms, the narrow purple, pink, and lavender petals arranged to closely resemble an orchid. These flowers appear on the trees from September through November and are a beautiful sight to see, creating a vivid splash of color in the autumn landscape. The flowers are followed by 12-inch-long, slender, brown, flat seed pods which usually persist on the tree throughout the winter. Fruit brown, strap-shaped, not septate, elongated dehiscent pods, ca. 15-30 cm long, up to 1.5-2.5 cm wide, containing 10-15- shiny-brown, glabrous, dehiscent, rounded, flat seeds; twists as opens. Seed forms very rapidly and trees in flower may already show numerous green pods. While most pods will open in the drier winter weather some may persist through to the next flowering season. Fruit maturing in spring and summer. Fruit does not attract wildlife. Seeds orbicular, 13-16mm in diameter, 1-2mm thick. 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 purple colour of the flowers. There are about 300 species of this genus found in tropical regions. The genus includes trees, vines, and shrubs that are frequently planted for their showy flowers and ornamental foliage. There is a presence of stomata on the seeds and pods.
Ecology
B. purpurea is a plant of tropical and subtropical climates usually found in most types of vegetation ranging from evergreen lowland rain forest to mountain forest and savanna, scrub and dry deciduous forest to swamp foreston various soils. It occurs at lower elevations especially frequent along the valleys in its native habitat. It demands plenty of light and requires good drainage. Severe frost kills the leaves of seedlings and saplings, but they recover during summer. The species is frost-hardy but least drought-hardy compared to other species of Bauhinia. The tree actually flower best on dry soils.
Native range
Bangladesh, Bhutan, China, India, Indonesia, Japan, Malaysia, Myanmar, Nepal, Pakistan, Sri Lanka, Taiwan, Province of China, Thailand
Tree management
B. purpurea should be grown in full sun on well-drained soil. For successful establishment of Bauhinia, protection from grazing or browsing for the first 2-3 years is necessary, because the young saplings are much relished by animals. In regular plantations, the trees should be kept adequately thinned as they grow. The tree may need occasional pruning to develop a uniform shape when it is young. Growth rate is relatively good in lower altitudes but above 1600m, growth is very slow and plantation scarcely justified. The tree coppices well and can stand heavy lopping fairly well. It 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. Branches tend to develop low on the trunk and droop toward the ground forming a large bush if left unpruned. The species has a tendency to show nutritional deficiencies, especially potassium. Trees are frost- and drought-tolerant and flower best on dry soils. The species is reported weedy in gardens in Hawaii.
Seed storage behaviour is orthodox; viability maintained for 3 years in hermetic storage at room temperature. There are 4000-5000 seeds/kg. About 600 to 1900 plants are raised per Kg of seed.
B. purpurea is a plant of tropical and subtropical climates usually found in most types of vegetation ranging from evergreen lowland rain forest to mountain forest and savanna, scrub and dry deciduous forest to swamp foreston various soils. It occurs at lower elevations especially frequent along the valleys in its native habitat. It demands plenty of light and requires good drainage. Severe frost kills the leaves of seedlings and saplings, but they recover during summer. The species is frost-hardy but least drought-hardy compared to other species of Bauhinia. The tree actually flower best on dry soils.
Propagation is by seeds, grafting, cuttings, and air-layerings and is reported in many countries especially in southeast Asia. Bauhinia reproduces itself naturally from seeds, as pods open on the trees during hot season, scattering the seeds which germinate with the start of the rains. Regeneration is sometimes plentiful in fresh soil deposits on landslips under seed-bearers but in most cases is scanty because birds and insects destroy most of the seed lying exposed on the ground. Bauhinias should preferably be grown in full sun in fertile, moisture-retentive but well-drained soils. Artificial propagation is through direct sowing and stump planting. Seeds give a good germination rate of 85-95%, beginning 5-10 days after sowing and is completed 1-2 weeks later. Both methods are quite successful and considered better than planting out 1-year-old seedlings. Branch cuttings root only with difficulty but cuttings of semi-ripe wood with leaves removed will root in moist sand root well.
Erosion control: Bauhinia purpurea with a deep root system and high root: shoot ratio may be a suitable species for slope stabilization.
The young leaves and flowers of various Bauhinia species are eaten as a side dish with rice, or used to flavour meat and fish. Sometimes the seeds are edible.
In an experiment in Nepal, B.purpurea was found increase milk production in lactating buffaloes. Leaves make good fodder and are greedily eaten by sheep, goats and cattle with protein content estimated at 12.6%.
Used as fuelwood; its calorific value is 4 800 kcal/kg.
Fibre: The bark of bauhinia is used to make rope and stems of smaller lianescent species are used for binding. Some bauhinia species are used for binding. Some bauhinia species reputed for their fibre application are used medicinally as well.
Timber: The wood is used for agricultural implements.
Tannin or dyestuff: The bark of various bauhinia species contains considerable amounts of tanninwidely used in leather industry in India. Medicinal uses of bark can be largely attributed to the presence of these tannins. Flavonoids are a common feature of Bauhinia.
Lipids: The seeds contain high amounts of linolenic and oleic fatty acids (15% of a non-drying oil) and low amounts of myristic and linolenic fatty acids.
Medicine: Throughout South-East Asia various parts of numerous Bauhinia species are used in poulticing to reduce swelling and bruises, and to ripen ulcerations and boils. Decoctions of various plant parts are taken internally as a febrifugal, antidiarrhoeal and antidysenteric remedy and also it is used as an astringent. In India, the bark is extensively applied in glandular diseases and as a poison antidote while the leaves are administered as cough medicine. The flowers are said to be laxative and used in curries and pickles.
Gum or resin: The tree yield edible gum.
Ornamental: B. purpurea is widely planted as an ornamental tree in parks, gardens and homesteads, and along avenues for its showy fragrant, purple flowers. The weak wood is susceptible to breakage in storms; the abundant seedlings, which may germinate in the landscape; and the litter problem, created by the falling leaves, flowers, and seedpods.