<i>Koenigia bingchachaensis</i> (Polygonaceae), a Remarkable New Species from the Alpine Subnival of Bingchacha, Zayü, Xizang, China

ABSTRACT A new species, Koenigia bingchachaensis Bo Xu &amp; H. Sun (Polygonaceae), is described and illustrated based on material from the alpine subnival of Zayü County, Xizang, China. The species is characterized by a perennial tufted habit, extensively developed braided‐fissured rhizomes, numerous simple spreading stems, prominently petiolate (1.5–4.0 cm) and arched leaves, and paniculate inflorescences borne both terminal and axillary with a short, twisted rachis. Morphologically, it is closely allied to K. tortuosa and K. hookeri , but can be readily distinguished from both by a stable combination of vegetative and reproductive characters. Molecular phylogenetic analyses based on complete plastome and nuclear ribosomal ITS sequences strongly support K. bingchachaensis as a distinct species, resolving it as a well‐supported sister lineage to the clade comprising K. hookeri and K. tortuosa . The integrative taxonomic approach, combining detailed morphology with molecular data, unequivocally confirms the specific status of K. bingchachaensis . The discovery expands the known diversity of Koenigia and highlights the potential for uncovering unique plant lineages in the extreme alpine environments of the Qinghai–Tibet Plateau.