Lilium pseudonanum, a cryptic species endemic to highly restricted habitats within the eastern Himalayas, has been identified and taxonomically distinguished from the morphologically similar L. nanum Klotzsch. Genetic analyses utilizing nuclear and chloroplast datasets have conclusively established L. pseudonanum as a separate species, revealing no close phylogenetic relationship to L. nanum, despite their historical treatment as conspecific. Morphological principal component analysis (PCA) indicated no pronounced differences between the two species, apart from notably larger basal leaf blades in L. pseudonanum, underscoring its cryptic nature. Furthermore, these species display ecological niche divergence; L. pseudonanum occupies habitats characterized by higher summer precipitation and prolonged snow accumulation during winter, providing increased moisture availability relative to the drier habitats of L. nanum. Environmental niche modeling (ENM) predicts that the potential range of L. nanum may shift due to global warming, potentially driving upward migration to higher elevations or latitudes. This movement could result in overlapping habitats with L. pseudonanum, raising critical concerns about habitat loss and the risk of genetic introgression. Such genetic mixing may compromise the taxonomic distinctiveness and ecological stability of L. pseudonanum. Given its extremely restricted geographic range and small population size, L. pseudonanum is designated as ”Critically Endangered” (CR). Consequently, urgent actions to verify its taxonomic status and implement comprehensive conservation measures are vital for its survival.