Description:
Aristolochia bidoupensis Do sp. nov. is newly described. This new species, currently only known from southern Vietnam, is most similar to Aristolochia faviogonzalezii (northern Vietnam) and A. moupinensis (China), but can be distinguished from the latter two by the following characters: flowers terminal, axillary, solitary, peduncle 1.3–1.5 cm long, bracteole ovate, 3–4 × 2–3 mm, limb discoid‐shaped with three expanded lobes, not revolute, internal surface uniformly dark purple, smooth, throat uniformly golden without dots. Morphological characters such as a 3‐lobed gynostemium and a 3‐lobed limb place the new species in A. subgen. Siphisia.