A wild orchid rediscovered after 198 years

Photo: A bloomed flower by author.

A total of 188 species of orchid so far recoded from Bangladesh and rich species diversity is found in the genera Dendrobium with 27 species. Two eminent Botanists (Sir Joseph Dalton Hooker and Sir David Prain) was worked for the flora of British India and published two famous books (The Flora of British India and Bengal Plants). In their books, they listed many species, and many species were not reported a second time from the current part of Bangladesh.

Generally, the species found after 100 years in the wild, will be considered as newly rediscovered species. Dendrobiumangulatum is rediscovered from Bangladesh and it is published in the international journal Tropical Plant Research. This is a poorly known species in Bangladesh and there was only a reported sample preserved in Kew herbarium which was collected by De Silva in 1821.

The field exploration in Sangu Reserve Forest focusing particularly to know the flora, fauna along with river and riverine life associated with this remote forest during February 2019. During random walking inside the forest, an orchid plant without flowering was found on a branch of huge tree species of the genus Dipterocarpus placed down on the forest floor.

The tree was found inside the forest as chopped down by an unknown and illegal wood collector. Few living plants have been collected for further investigation about flowering, as a sample for the preparation of herbarium specimen and future reference to identify the orchid species.

The plants were kept at the resident balcony where adequate sunlight and shade is available. Careful observation was made on its flowering and fruiting. At the end of March 2019, several flowering buds evolved from the node of the branch, and the flower finally fully bloomed on 4th April 2019 and other flowers sequentially blooming until July 2019. A single fruit also was observed in May 2019, matured, and dried up within one month.

A thorough close looked at the preserved specimens in Kew Herbarium from the online Kew Herbarium Catalogue, which were collected from India and Myanmar and reviewed of published literature and through examined of the floral characteristics, the plant finally identified, which was previously reported close to 200 years ago. It has reported this species possibly lost from Bangladesh in 2017. This species was not found from its previous occurring area during their survey and its state of occurrence was unknown stated in the published research book by Bangladesh National Herbarium in 2018.

It is an epiphytic herb and the stem is 40–100 cm long. The leaves are 3–12 per branch and the inflorescence is single-flowered, arising from tubercles at upper nodes or leaf axils. The flowers are small, 1.0–1.2 cm long, white with pink lines on the lip. It grows on tree trunks in subtropical rain forests; up to 247 meter altitude in Bangladesh. Flowering and fruiting from April to July in Bangladesh based on recent observation. It is found in India (Assam), Bangladesh, Myanmar, southwestern Thailand, and Vietnam.

No extensive surveys yet to be carried out at its recently found habitat area. But appear to be limited and restricted inside little vegetation patched of SRF of Thanchi of Bandarban District. The population seems to be decreasing due to host tree feeling by timber poachers and forest clearing for paddy cultivation on hill slope by the indigenous community. It is recommended for further extensive investigation on its recently found habitat area to implement future conservation measures and determine the IUCN regional conservation status. There is no local name for this orchid.

Author: Nature and Environment Columnist

Note: The article was published in Bengal Discover print version in 2021.