Aristolochia kaoi T. S. Liu & M. J. Lai.

Herbs twining. Stems terete, glabrous. Petiole 3-6 cm, glabrous; leaf blade ovate-lanceolate to lanceolate, 5-15 × 2-3 cm, leathery, abaxially densely puberulous along closely reticulate veinlets, adaxially glabrous, veins palmate, 2-3 pairs from base, base deeply cordate or auriculate, sinus 1-2.5 cm deep, lateral lobes overlapping or slightly incurved, apex acuminate. Racemes in axils of leafy shoots, 3- or 4-flowered or flowers almost fascicled, 2-3 cm. Pedicel ascending, 1-1.5 cm, sparsely villous; bractlets ovate or lanceolate, 4-5 × 2-3 mm. Calyx purple-brown; tube rectilinear or slightly curved, abaxially glabrous; utricle globose, ca. 6 mm in diam., sessile; tube ca. 20 × 6 mm; limb unilateral, ligulate, ovate-oblong, ca. 2 × 1-1.6 cm. Anthers elliptic, ca. 1 mm. Gynostemium 6-lobed. Capsule cylindric to obovoid, 2-2.5 × 1.5 cm, dehiscing acropetally. Seeds ovoid-deltoid, ca. 5 × 4 mm. Fl. Jul-Aug, fr. Aug-Oct.

Thickets on mountain slopes; 500-1000 m. Taiwan [Philippines].