Amid encroached forests, Assam’s Sonai Rupai yields a new botanical treasure

Guwahati: Deep in the lush forests of Assam’s Sonai Rupai Wildlife Sanctuary, a quiet discovery has added a new chapter to India’s botanical story. A team of researchers from the Department of Botany, Gauhati University, has identified a previously unknown plant species — Ardisia assamica Baruah, Saikia & Devi — marking a proud moment for the state’s growing list of floral treasures.

Belonging to the Primulaceae family (subfamily Myrsinoideae), Ardisia assamica stands tall at 2 to 4 metres, its young branches glinting with a faint rusty hue under the forest light. Its elegant, lance-shaped leaves form spiral whorls, while clusters of soft pink to pinkish-white flowers bloom gracefully, each petal adorned with delicate white blotches and golden-yellow-tipped sepals. When the season turns, these blossoms give way to glossy black fruits that distinguish the species from its close relatives, A. quinquegona and A. quinquangularis.

With this discovery, the number of Ardisia species recorded from Assam has increased to 14. In  India, the genus is represented by 32 species.

Encroachment has hit the sanctuary hard, with the Assam government informing the National Green Tribunal (NGT) of the encroachments and non-forest activities taking place inside the sanctuary. Out of the 220 sq km of eastern wet alluvial grasslands, moist deciduous, and semi-evergreen forests, most parts have been encroached upon.

“The moment we saw its floral structure and fruiting pattern, we knew we were looking at something distinct,” said one of the lead researchers, reflecting on the team’s field explorations. “Its inflorescence, the triangular ciliate sepals, and non-pentahedral fruit set it apart clearly from any known Ardisia species.”

The flowering phase of A. assamica stretches from March to May, with fruits ripening between June and July — a subtle seasonal rhythm that mirrors the monsoon’s onset across Assam’s foothills.

The discovery, formally published in the international journal Phytotaxa (2025), not only enriches Assam’s flora but also underlines how much of the region’s biodiversity remains to be unveiled. The researchers have dedicated the species epithet “assamica” to the state where it was first found, a fitting tribute to Assam’s role as a biodiversity hotspot in the Eastern Himalayas.

The holotype specimen is now preserved in the ASSAM Herbarium, with duplicates at the Gauhati University Botanical Herbarium (GUBH) — ensuring that this delicate forest beauty is catalogued for future generations of botanists.