There are myriad flowering trees that enjoy sovereignty in a wide range of habitats. Among them is the tree of heaven (Amherstia nobilis Wall.) or Simsapa, as it is locally known, a medium sized evergreen tropical tree. Amherstia is so rare that it has been collected from the wild only a couple of times in the forests of Myanmar. The breathtaking beauty of the flowers along with its obscurity adds to the mystique of this glorious tree.
Amherstia is monotypic, i.e., the only member of the genus belonging to the family Caesalpiniaceae. The genus ‘Amherstia’ was named after the Countess Amherst, wife of a former Governor of Burma and her daughter Lady Sarah Amherst, who collected this plant in the early 19th century. The specific appellation ‘nobilis’ comes from the honour bestowed upon the tree. According to the available data, Amherstia was found in a temple garden in Burma (Myanmar) in 1826
which enabled it to earn the epithet ‘pride of Burma’. Later on, noted Botanist Sir Nathaniel Wallich (Director of Botanical Gardens at Kolkata in the 1830s) named the binomial and described it as a superlative wonder in the world of flowering trees.
Apart from Myanmar and India, Amherstia is found in the gardens of Peninsular Malaysia, Java, Sri Lanka, Thailand (in Asia); Papua and New Guinea (in Australia), El Salvador (in Central America), Brazil (in South America) and in Caribbean Islands, Seychelles and Northern Marianas (India Ocean Islands and Pacific Islands, respectively). However, it is assumed that Amherstia nobilis is extinct in the wild as it has not been sighted in forests since 1856.
A sacred tree
Amherstia is considered to be a sacred tree by the people of South East Asian countries. Its flowers are treated with reverence in Myanmar and Sri Lanka. A handful of its flowers are offered before images of Gautam Buddha and it is for this reason alone that the tree is found in many Buddhist temple gardens. India too has temple gardens and ‘sacred groves’, a culture that can be traced from time immemorial, but Amherstia is not seen here. It is at best treated as an ornamental tree mainly found in parks and gardens, as an element of landscaping, particularly in eastern and southern India.
Amherstia and Ecosystem
The petite Amherstia is a small to medium sized tree of about 5-8 metres high. The stout tree trunk has uneven, dark ash-grey bark. The wood is soft and whitish. When not in flower, Amherstia looks similar to another well-known sacred tree Ashoka (Saraca indica). Young leaves are coppery red to purple, flaccid and remain pendent even after attaining full maturity. Amherstia flowers twice in a year, i.e., in April and in October, the flowers lasting for only two or three days. The exceptionally beautiful flowers are seen hanging from the long candelabra-like racemes arising in the axil of the leaves. The arrangement of petals sometimes resembles orchid flower. Hence, the tree is also known as the ‘orchid tree’.
Amherstia show myrmecophily, a symbiotic association between plant and ant in the ecosystem as certain wood ant genera like Camponotus, Crematogaster, Dilobocondyla, Formica, Tapinoma, Technomyrmex, etc., inhabit Amherstia tree. The ants benefit by receiving food and nest site while the plant benefits by receiving protection for seed dispersal. The fruit is a roughly scimitar-shaped flat pod, 11-20cm long and is beaked like other leguminous fruits. After maturity the woody outer case opens to disperse the seeds.
Care for the rare tree
Amherstia prefers rich moist soil and partial shade along with a humid but warm climate. Perhaps that is why it can be successfully planted in eastern and southern India. In northern India Amherstia is unable to survive due to hot dry winds and frosts which damages the plant.
According to the IUCN Red List (January, 2003), Amherstia is an endangered species, attributable perhaps to habitat loss and climate change. Loss of natural habitat due to destruction of forests to fulfil the requirements of agricultural, industrial and mining along with unplanned growth of urban centres is the basis of its disappearance. Pollution problem, introduction of exotic species and complete disregard for the ecological inter-relationships among native species within a certain geographical region are some other reasons for the threat being faced by Amherstia. Presently, this tree of beauty and rarity deserves attention by all those who want to make the world a better place.