Dalzellia ubonensis (Podostemaceae): A New Record for India Evidenced by Morphological Characters and Phylogenetic Analysis.

ABSTRACT: Dalzellia ubonensis M. Kato (2006), previously known only from Laos, Thailand, and Vietnam, is reported here for the first time from India, specifically from the Kallar River in the Vadasserikkara Range, Pathanamthitta district, Kerala. Detailed morphological examination revealed key diagnostic traits—absence of roots, broad crustose shoots, rosette leaf arrangement, and numerous ovules—that match the protologue of D. ubonensis and distinguish it from other Indian congeners, particularly Dalzellia gracilis. For molecular confirmation, genomic DNA was extracted and the plastid matK region was amplified and sequenced. BLASTn analysis showed ≥98% sequence identity and 100% query coverage with reference Dalzellia sequences in GenBank, corroborating its identity as D. ubonensis. This integrative taxonomic approach—combining classical morphological taxonomy with DNA barcoding—confirms a significant range extension for the species and represents the first verified record of D. ubonensis in India. This finding highlights the floristic uniqueness of Kerala’s riverine ecosystems and underscores the need for targeted exploration and conservation of aquatic Podostemaceae taxa in understudied regions of the Western Ghats.