Rare Occurrence of Butea monosperma (Lam.) Taub. var. lutea (Witt.) Maheshwari in Kalahandi and Its Adjoining Areas of Odisha, India

The genus Butea (Fabaceae) holds ecological and medicinal significance, with Butea monosperma (Lam.) Taub. widely recognized for its traditional uses. A rare variety, Butea monosperma var. lutea (Witt.) Maheshwari, distinguished by its yellow flowers instead of the typical orange-red, has been recorded in Kalahandi and adjoining areas of Odisha. Limited reports on its occurrence make it essential to assess its distribution, diversity, and ecological significance. This study evaluates its occurrence, morphological characteristics, habitat preferences, and biodiversity significance using quantitative ecological indices. Field surveys conducted from 2023 to 2024 across Kalahandi, Nuapada, Balangir, Kandhamal, and Boudh districts in Odisha employed quadrat sampling (10 × 10 m plots) for vegetation diversity assessment, with morphological identification performed through comparative analysis with Butea monosperma using standard taxonomic keys. Species diversity was analyzed using the Shannon-Wiener Index (H') and Simpson’s Index (D). A total of Nine individuals were recorded across five districts, with an H' value of 2.04 and a D value of 0.136, indicating moderate habitat diversity but low dominance. The variety was found at elevations of 200–600 m, primarily in moist deciduous patches alongside Shorea robusta, Terminalia arjuna, and Madhuca indica. Morphological differences from Butea monosperma included pale yellow flowers, slightly pubescent leaves, and shorter fruit length (12–18 cm). The discovery of Butea monosperma var. lutea in Odisha enriches the region’s floristic diversity and underscores its ecological significance. Its restricted distribution and low population density highlight the need for conservation strategies, while further research is required to explore its phytochemical properties, genetic diversity, and potential applications in traditional medicine.