Nanhaia, with two species, is readily distinguished from Wisteriopsis by the densely pubescent or sericeous ovaries (glabrous in Wisteriopsis) and the larger flowers frequently 15–35 mm long (vs Wisteriopsis 7–15 mm long). In Nanhaia the stipules arise immediately above the swollen, hardened gibbosities (Fig. 4).

Nanhaiaspeciosa (Champ. ex Benth.) J.Compton & Schrire ≡ Millettiaspeciosa Champ. ex Benth.

Procumbent or scandent twining vines, 1–5 m high, scrambling among rocks and scrub. Stems green or brown, terete, pubescent. Leaves with 5–17 leaflets, evergreen, glabrous or with a few scattered hairs below, imparipinnate, rachis 3–30 cm long. Stipules 2–4 mm long, linear or deltoid, caducous in N.fordii (persistent N.speciosa). Stipels 1–3 mm long, linear, persistent. Leaflets 3–9 × 1–4 cm, ovate-elliptic or narrowly elliptic, glabrescent or sparsely hairy, apex acuminate or cuspidate, margins entire, base rounded to subcordate. Inflorescence erect or pendant sometimes leafy panicles 4–20 cm long, frequently comprising several leafy lateral racemes, peduncle yellow tomentose or densely brown pubescent. Flowers 16–32 mm long, emerging from June to September. Floral bracts 3–7 mm long, linear or narrowly deltoid, persistent (caducous in N.fordii). Bracteoles at base of calyx 1–5 mm long, narrowly ovate or elliptic, persistent. Pedicels 4–11 mm long, glabrous or pubescent. Calyx 4–6 × 5–9 mm campanulate, oblique, pubescent externally, (densely pubescent internally on N.fordii) five lobed, teeth unequal, 1–3 mm long, acute. Standard 12–18 × 11–18 mm, suborbicular, white, cream or pink, nectar guide pale or dark green, back of standard glabrous, apex acute or obtuse. Callosities of boss type. Wing petals 12–17 × 4–6 mm, glabrous, subequal to the keel, each narrowly semi-pandurate, slightly curved upwards at the apex; free from the keel, apex obtuse, basal claws 2–5 mm long. Keel petals 12–16 × 4–6 mm, glabrous, united into a falcate, navicular cup, apex obtuse, basal claw 4–9 mm long. Stamens diadelphous, nine fused together, the vexillary one free, all curved upwards at apex. Ovary densely sericeous, especially along thickened margins, style ciliate (N.speciosa) or glabrous (N.fordii), 2–3 mm long curved upwards at apex, stigma punctate. Pods 10–20 × 1–2 cm, flat, linear, dehiscent, surface pubescent to densely brown tomentose, brown and hard when dry, subseptate. Seeds 2–10, ovoid or ellipsoid, 10–12 × 5–12 × 1–7 mm, hilum terminal or central, elliptic, 2–3 × 1 mm. Fig. 4.

China (Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hunan, Yunnan); Vietnam (north).

Nanhai is the Chinese name for the South China Sea which links southern China with Vietnam.