Guwahati: In a remarkable find for both botany and biodiversity conservation, researchers have identified a new orchid species in the bamboo thickets of the Tezu region in Arunachal Pradesh’s Lohit district.
The newly discovered species, named Gastrodia lohitensis, joins India’s catalog of rare orchids and contributes to the global diversity of the Gastrodia genus, known for its unusual leafless and subterranean lifestyle. The team of botanists, led by Krishna Chowlu from the Botanical Survey of India, made the discovery during a May 2024 expedition.
The discovery of Gastrodia lohitensis adds to the eight previously recorded Gastrodia species in India, five of which are endemic. Known for their holomycotrophic nature—deriving nutrients from fungi rather than through photosynthesis—these orchids are uniquely adapted to shaded environments. The plant, about 50-110 cm in height, thrives under bamboo canopies in dried leaf litter, blooming with elegant white flowers in April and May. The new species is named after the Lohit district of Arunachal Pradesh, where it was collected.
Microscopic analysis revealed distinguishing features that set G. lohitensis apart from related species. Unlike its close relative Gastrodia fimbriata, found in Thailand, the new species showcases two unique linear calli and ridges on the lip of its flower, setting it apart from other members of the Gastrodia genus. These features were further verified through cross-referencing with historical records and herbarium specimens from 1890 to recent studies in 2019.
Leafless and Holomycotrophic: Unlike typical plants, G. lohitensis is completely leafless and derives its nutrients from a symbiotic relationship with fungi rather than from photosynthesis. This adaptation is rare and allows the orchid to thrive in deeply shaded, forested habitats like bamboo thickets where sunlight is scarce.
Unusual Habitat Preference: It grows exclusively in semi-shaded areas on decomposing leaf litter under bamboo canopies. This specific ecological niche, combined with its reliance on fungal partners, makes G. lohitensis highly specialized.
G. lohitensis is so far only known to grow in a small region within the Lohit district of Arunachal Pradesh, adding to India’s list of endemic orchids. Its unique adaptations and limited geographic range underscore its conservation value and vulnerability.
As it stands, G. lohitensis is categorized as “Endangered” on a provisional basis, following the International Union for Conservation of Nature (IUCN) guidelines. Its habitat faces pressures from local activities like bamboo harvesting and agriculture, endangering the species’ fragile ecosystem. Researchers emphasize the urgent need for conservation efforts to protect this rare orchid, which could potentially be found in other forested regions nearby.
The discovery of Gastrodia lohitensis highlights the rich but threatened biodiversity in Arunachal Pradesh, underscoring the importance of preserving these unique habitats to safeguard rare and endangered species.
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