Glabrous perennial with thick rootstock and slender stems, climbing by means of slender coiling petioles up to 4 cm long. Lvs digitate; leaflets 5, subsessile or with petiolules to 1 mm long. Lamina of terminal leaflet 1-3 × 0.4-1.3 cm, ovate to ± broad-elliptic, entire; base cuneate; apex obtuse or subacute; other leaflets smaller, especially the basal pair. Fls solitary; pedicels > lvs, to c. 14 cm long, pinkish. Calyx regular; sepals 8-11 mm long, triangular or broadly triangular, green with red dashes within, accrescent and pink at fruiting; spur 2-2.5 cm long, gradually ampliate from swollen distal part, deep pink except for mauvish distal area. Corolla very irregular with only upper 2 petals developed; petals 3-6 mm long (including stalk-like claw 1-2 mm long), scarlet; limb < 5 mm long, elliptic or broad-ovate. Anthers green; filaments streaked red. Frs thinly fleshy; carpels subglobose, often 1-2 remaining small; fertile carpels c. 7 mm diam., becoming dark blue.