Guwahati: In a breakthrough that underscores both the biological richness and fragility of Northeast India, botanists from Mizoram University and Manipur University have discovered a new plant species, Argostemma sawmlianae, from a forest stretch near Lungleng village, just 20 km from Aizawl.
The finding, published in the journal PhytoKeys, places Mizoram once again in the spotlight of global biodiversity research.
Between June 2022 and October 2024, botanical field explorations in Mizoram led to the collection of an unidentified Argostemma species from the forests of Lungleng village.
Mizoram, located at the confluence of the Indo-Malayan and Indo-Chinese biogeographic regions—both part of the Indo-Burma Biodiversity Hotspot—is known for its remarkable floral diversity, including numerous endemic species.
Argostemma sawmlianae, belonging to the coffee family Rubiaceae, is a delicate epilithic herb that grows on damp rock walls along shaded streams. Despite its botanical distinctiveness, its existence is extremely precarious: researchers recorded only 39 mature individuals, all confined to a single patch of forest.
Road expansion, landslides, and continual habitat disturbance place the species “one extreme event away from disappearing,” the authors warn.
The species is notable for its striking features—large unequal leaves, a campanulate corolla with white petals that curl dramatically backward, and an unusually high flower count per cyme.
These traits set it apart from its closest relatives, A. courtallense and A. sarmentosum.
To confirm that it was indeed new to science, the research team combined classical morphological study with Scanning Electron Microscopy (SEM) of its seeds and pollen, along with DNA barcoding using matK and ITS2 gene sequences. Molecular analysis confirmed that the species forms a distinct lineage within the Argostemma group.
The species has been named sawmlianae in honour of Mal Sawmliana, a respected forest conservator and naturalist known for his contributions to documenting Mizoram’s flora.
“This finding reminds us how much biodiversity remains hidden in these fragile ecosystems—and how quickly it may vanish if not protected,” said Dr. Khomdram Sandhyarani Devi, one of the lead authors.
Dr. Yumkham Sanatombi Devi added, “Discovering a second Argostemma species from Northeast India reinforces the urgency of documenting biodiversity before it disappears unnoticed.”
With its entire population restricted to a single vulnerable location, the species has been provisionally classified as Critically Endangered under IUCN criteria. The roadside habitat where it grows faces recurring landslides and ongoing development, greatly increasing its extinction risk.
This is the second Argostemma species described by the same research team from the region, following the discovery of A. kamjongense in Manipur. Together, these findings highlight the underexplored flora of the Indo-Burma Biodiversity Hotspot and the urgent need for targeted conservation, especially as development accelerates.
The discovery of Argostemma sawmlianae is both a celebration of Mizoram’s natural heritage and a stark warning: even as new species continue to emerge, their survival remains far from guaranteed.
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