Aristolochia kechangensis sp. nov. (Aristolochiaceae) from Guangxi, China

Aristolochia kechangensis Y. D. Peng & L.Y. Yu, a new species from northwestern Guangxi, China, is described and illustrated. Based on morphology, the species is referred to Aristolochia subg. Isotrema. The species is similar to A. kwangsiensis and is found in karstic limestone habitats, with ovate-rounded to heart-shaped blades and 1-4-flowered racemose inflorescences, but differs from the latter by a heart-shaped (versus rounded) blade base, yellow-green limbs with densely brown nervules (versus red to purple limbs with tuberculate ornamentation), and slender fruit with a diameter of ca 1.5 cm (versus robust fruit with a diameter of ca 2 cm). The leaf epidermis of the new species is characterized by tuberculate protuberances. We present a detailed description, with line drawings, distribution map and color plate, and compare it to related species based on morphological characters. An updated key to Aristolochia distributed in Guangxi region is provided.