8. Mucuna revoluta Wilmot-Dear, Kew Bull. 47: 222. 1992.
卷翅荚油麻藤 juan chi jia you ma teng
Twining vines, ± woody. Stems glabrous or with sparse adpressed fine hairs. Leaves up to 20 cm; petiole up to 9 cm, often hairy; stipels 2-4 mm; leaflets thinly papery, hairy (rarely glabrous) on both sides, lateral veins 4 or 5 pairs, gently curved; terminal leaflet elliptic or ovate, 8-10 × 4-5.5 cm, base narrowly rounded, apex abruptly acuminate; lateral leaflets up to 12 cm, width ratio of abaxial to adaxial halves 1.75-2:1, base of abaxial half truncate, base of adaxial half rounded to cuneate. Inflorescences (3-)8-16 cm, unbranched or once or twice branched near base, without flowers in lower 1/3 of axis, nodes 5-13; bracts caducous, widely varying in size and shape, elliptic or obovate to linear-oblong, (5-)10-17 × (2-)5-7, with sparse minute fine spreading hairs; bracteoles similar to bracts, longer than calyx; pedicels 5-10 mm, with dense minute (0.1-0.2 mm) fine spreading velvety light brown hairs. Calyx with dense minute hairs like pedicels and irritant red bristles; tube ca. 8 × 8-10 mm; lobes conspicuous, laterals 4-6 mm, lowest 8-9 mm, all broadly triangular with abrupt fine acumen. Corolla deep purple or pinkish purple with paler keel (rarely all petals white); standard ca. 3 × 2 cm, ca. 2/3 keel length; wings 4.5-4.8 × ca. 1 cm; keel equaling wings. Legume broadly oblong, sometimes asymmetric, with rounded apex and base, 6-9 × 4-4.5 cm, up to 2.5 cm thick, leathery, with minute spreading hairs and abundant irritant bristles, both margins with a pair of strongly inrolled wings ca. 4 mm wide, both surfaces with 8-12 thickly leathery markedly obliquely transverse crowded parallel lamellae completely concealing fruit surface, each divided along their margin into 2 wings up to 5 mm broad and strongly revolute, lamellae uniformly interrupted along midline of legume and not extending into marginal wings of fruit. Seeds (1 or)2, shiny, red-brown with black mottling, very large, 2.5-2.8 × ca. 2 cm; hilum just over 1/2 circumference of seed.
Forests and disturbed vegetation, seasonal rain forests often by streams, dry evergreen forests, primary and slightly disturbed evergreen hardwood forests, swamp forests, degraded caducous forests and bamboo, scrub, roadsides; 300-800 m. W Yunnan [Cambodia, Laos, Thailand, Vietnam].
The original material of Mucuna revoluta was included within M. interrupta. Mucuna revoluta is distinctive in its legumes with strongly inrolled marginal wings and rigid thick-textured lamellae, which are divided distally into 2 wings, interrupted along the midline of the legume, strongly revolute, and not extending into the legume wings, and in its minute spreading velvety pubescence on the flowering parts (in most other species hairs are at least 0.4 mm, often adpressed). Mucuna interrupta and M. hainanensis have almost identical leaves; M. interrupta differs by the longer usually adpressed indumentum on its flowering parts, by the flowers always white with longer wings and keel, and by the legume with thinly textured upcurved lamellae and flat or undulating marginal wings. Mucuna hainanensis is distinguished by the adpressed hairs on flowering parts and the fruit with simple lamellae mostly not interrupted along the midline.