Deciduous woody climber; stems 6-angled, strongly ribbed. Lvs sparsely hairy, green, 1-pinnate, 12-20 × 8-16 cm; leaflets usually 5, rarely 3, thin, ovate, rarely lanceolate, truncate or cordate at base, acuminate; margin entire or toothed; lvs of young growth narrower, thinner, hairier, and more deeply toothed; petiole (3)-4-8 cm long, with sparse to dense fine silky hairs. Fls erect, ☿, in compound axillary dichasial cymes. Bracts paired, spathulate to subulate, not united, inserted below middle of pedicel. Sepals 4-(5), valvate, greenish, densely hairy above and beneath, especially near margins, narrowly oblong to oblong-obovate, obtuse, 6-11-(15) × 2-4 mm. Anthers 1.5-2 mm long; filaments glabrous, linear. Achenes compressed, hairy, 2-2.5 mm long. Style 3-4 cm long at fruiting.