Shweta-khadira: A Narrative Review of Its Botanical Identity

Abstract

The naming of medicinal plants on the Indian subcontinent has changed considerably across successive historical periods, moving from the Vedic age through the Puranic and Samhita periods, into the Nighantu tradition, and finally into the framework of modern taxonomy. In the Vedic period, as reflected in the Atharvaveda, plant names were largely experiential and symbolic, drawn from observable features, practical use, and spiritual significance; this practice frequently generated several names for a single plant and produced ambiguity in identification. A comparable pattern persisted through the Puranic period, illustrated in texts such as the Agni Purana, where religious and mythological associations shaped plant nomenclature. During the Samhita period, represented chiefly by Charaka Samhita and Sushruta Samhita, naming became somewhat more systematic and clinically grounded, being based on guna, karma, and therapeutic value, although exact botanical identification remained largely absent. A notable advance took place during the Nighantu period, particularly in compilations such as Bhavaprakasha Nighantu and Dhanvantari Nighantu, where plants began to be described with greater attention to morphology, properties, and habitat. Even so, the coexistence of numerous synonyms (paryaya) for one drug, together with the application of a single name to different plants (anekarthata), continued to complicate identification. Modern nomenclature, in contrast, rests on the Binomial system introduced by Carl Linnaeus, which assigns each species a unique and universally recognised scientific name. This divergence between traditional and contemporary naming systems underlies many of the difficulties encountered when classical Ayurvedic drug names are correlated with precise botanical identities—an issue clearly illustrated by Shweta Khadira, a name under which more than one species, including Senegalia polyacantha and Senegalia ferruginea, has been interpreted.

Kadara and Somavalka, as described in classical Ayurvedic sources, constitute important medicinal entities and are more directly correlated with the entity later termed Shweta Khadira. It is notable that the expression Shweta Khadira itself does not appear in the earliest classical texts and seems instead to represent a later interpretive addition. Classical literature refers to several varieties of Khadira—namely Khadira, Kadara, and Irimeda—indicating that more than one type of this drug was recognised and employed in antiquity.²⁰ Over time, however, the precise botanical identity of Shweta Khadira or kadara has grown uncertain, owing to differing scholarly interpretations and the coexistence of multiple regional names applied to related species.

Within modern botanical scholars, several species of the genus Senegalia (previously classified under Acacia) have been put forward as possible sources. Of these, Senegalia polyacantha and Senegalia ferruginea are most commonly discussed in pharmacognostic literature. Although the two species share certain similarities and overlapping habitats, they differ with respect to specific morphological features, notably bark colour and other diagnostic traits, and this divergence complicates their correlation with classical descriptions and sustains uncertainty regarding correct identification.

Against this background, the present review critically examines classical Ayurvedic descriptions of Kadara and Somavalka in conjunction with available botanical evidence. Its objective is to systematically compare the morphological characteristics of the candidate species and to identify the most plausible botanical source of the later-conceptualised entity, Shweta Khadira.

Establishing the correct botanical identity of Shweta Khadira carries considerable importance for ensuring authenticity and standardisation within Ayurvedic practice. Accurate identification of the source material lowers the risk of adulteration and supports the preparation of formulations that are safe, consistent, and of high quality. It further enables practitioners and manufacturers to select the appropriate species with confidence, thereby preserving the integrity of classical preparations. Clear identification criteria also promote uniformity and regulatory compliance across the herbal sector. More broadly, this review offers a template for resolving comparable ambiguities elsewhere and reinforces the scientific credibility and global standing of Ayurveda