Aristolochia minjiangyuanensis, a new species of subg. Siphisia (Aristolochiaceae) from Fujian, China

Aristolochia minjiangyuanensis, a new species of Aristolochia subgen. Siphisia from Jianning County, Fujian Province, China, is described and illustrated. Morphologically, it differs in having usually narrower, narrowly ovate-cordate leaves with a long-acuminate or acute apex, a subobovate perianth limb with the lower lobe significantly longer than the upper two lobes and an unspotted inner surface, a smaller throat, and an indumentum predominantly composed of grayish-white velvety hairs. Phylogenetic analyses, based on the nuclear ribosomal ITS region (5.8S + ITS2) and the plastid trnK region, support the placement of A. minjiangyuanensis within the A. kaempferi group, while the trnK analysis further strongly supports a sister relationship between the new species and A. vestita. The new species can be distinguished from A. vestita by its subobovate perianth limb with a revolute apex and an inner surface without spots or stripes, subcircular throat, and predominantly grayish-white velvety indumentum. It differs from A. kaempferi mainly in the morphology and markings of the perianth limb and in having a cylindrical, velvety capsule.