Aristolochiazhuhaiensis, a self-supporting new species of Aristolochiaceae from Guangdong, China and notes on Aristolochiathwaitesii.

A self-supporting new species of Aristolochiaceae, Aristolochiazhuhaiensis Y.Fan Wang & Z.R.Guo, is described and illustrated from Zhuhai City, Guangdong Province, China. Morphologically, this species exhibits vegetative characters, including leaf blade shape and growth form, that are similar to Aristolochiathwaitesii Hook., the only other known taxon in Aristolochiasubg.Siphisia in Asia that is non-twining and self-supporting, native to southern Guangdong, particularly the Hong Kong Special Administrative Region. However, A.zhuhaiensis can be readily distinguished from A.thwaitesii by its unique floral morphology. The new species features a campanulate to funnel-shaped calyx limb densely covered with porcelain-white granular pustules. In contrast, A.thwaitesii has an elongated, concave tubular calyx limb with an adaxial surface that transitions from purple to pale yellow or white towards the apex, densely covered with recurved fleshy prickles. Aristolochiazhuhaiensis is endemic to Zhuhai City and has not been observed elsewhere. Detailed illustrations, photographic plates, a distribution map, a digitized holotype voucher specimen, a comparative table, and an identification key are provided to facilitate the differentiation of A.zhuhaiensis from A.thwaitesii.