Ipomoea kadsura Choisy, Mem. Soc. Phys. Geneve 6: 475. 1833; Piper arboricola C. de Candolle; P. futokadsura Siebold; P. subglaucescens C. de Candolle.

Climbers woody, dioecious. Stems rooting at nodes, ridged, sparsely pubescent when young. Petiole 1-1.5 cm, sometimes pubescent, sheathed at base only; leaf blade ovate or long ovate, 6-12 × 3.5-7 cm, ± leathery, abaxially usually pubescent on veins, adaxially glabrous, with uniformly scattered raised white glands, base cordate to rounded, ± symmetric, apex acute or obtuse; veins 5, apical pair arising up to 1.5 cm above base, others basal; reticulate veins conspicuous. Spikes leaf-opposed. Male spikes yellow, ascending, 3-5.5(-12) cm × ca. 2.5 mm; peduncle 0.6-1.5 cm; rachis hispidulous; bracts yellow, orbicular, ca. 1 mm wide, peltate, margin irregular, abaxially roughly white pubescent, ± sessile. Stamens 2 or 3; filaments short. Female spikes shorter than leaf blades; peduncle ca. as long as petioles; rachis and bracts as in male spikes. Ovary globose, distinct; stigmas 3 or 4, linear, pubescent. Drupe brownish yellow, globose, 3-4 mm in diam. Fl. May-Aug.

This species has been recorded from Fujian and Zhejiang, but the material from those provinces differs from typical Piper kadsura in having the abaxial leaf surface uniformly hairy and the peduncles much longer, and seems better regarded as a form of Piper wallichii. The epithet is frequently spelled "kadzura," but there does not seem sufficient justification to treat the spelling used in the protologue as an orthographic error. The synonym Piper arboricola C. de Candolle has nearly always been midapplied to material of P. sintenense.

Lowland forests, on trees or rocks; 200-1500 m. Taiwan [Japan, S Korea]