Herbs, climbing or erect; stems grooved, glabrous; rootstock stout, often tuberous,
perennial. Leaves alternate, repeatedly ternate, petiolate, exstipulate; leaflets entire,
ovate, spathulate, sometimes orbicular, equally or unequally acute or rounded, sometimes cordate at base, petiolulate; terminal leaflets often replaced by a branched tendril;
nerves 3 - 4 from or slightly above base. Flowers in lateral leaf-opposed pendulous
corymbs or umbels, pedicellate, bracteate. Sepals 2, small, caducous. Petals 4; outer
pair coherent and keeled, forming a compressed tube, spurred or gibbous at base,
hooded and divergent at tip; inner pair rather linear, crested, unguiculate, exposed at
mouth, with long slender claw and connivent hooded limb enclosing anthers and stigma.
Stamens 6, in 2 bundles of 3 each; filaments adherent to outer petals, middle anthers of
each bundle 2-loculed; lateral anthers 1-loculed; each bundle expanded at base into 1 -
2 nectar glands, enclosed by swollen base of outer petal. Ovary elongate, 1-loculed, few
to many-ovuled; style slender, stigmas flattened with 2 apical horns. Fruits capsular,
linear, cylindric, ellipsoid, ovoid, rotund, dehiscing by 2 valves, leaving placentae attached to persistent style. Seeds reniform, rather flattened, papillate, beaked on one
side, often bulged on either side at beak, arillate or not.
Western to Eastern Himalayas, Meghalaya, China, Siberia, Japan and N. America;
ca 20 species, 6 in India.
KEY TO THE SPECIES
1a. Racemes mostly 2 - 8-flowered; bracts and sepals fimbriate or toothed at base; fruits linear, more than 3.5 cm long, less than 5 mm long
2
b. Racemes mostly 8 -
14-flowered; bracts and sepals entire at base; fruits ovoid, less than 3.5 cm long,
more than 5 mm thick
3
2a. Stout herbs, up to 3 m high; leaflets up to 4 x 1 cm; racemes 6 - 8-flowered; fruits torulose; seeds 1-seriate, opaque
3a. Leaflets broadly ovate, 2.5 - 6 x 2 - 3 cm, prominently 3 - 6 -nerved from base; nectar glands short, thick, up to 1.7 mm thick, not hooked at apex
b. Leaflets ovate-elliptic or lanceolate, up to 3.5 x 2.5 cm, not prominently 5 - 7-nerved from base; nectar gland long, slender, less than 1 mm thick, hooked or not at apex
4
4a. Leaves ovate-elliptic; nectar glands 4 - 5 mm long. deflexed and strongly hooked at apex; fruits ovoid, ellipsoid with long persistent style
b. Leaves narrowly ovate-lanceolate; nectar glands ca 3.5 mm long, deflexed but not hooked at apex; fruits narrowly ellipsoid, acute at both ends, rather elongated
5
5a. Leaflets greyish when dry, about 1.5 - 3 x 0.6 - 1.4 cm; petals ca 6 mm long; capsules generally rounded at base
