间序油麻藤 jian xu you ma teng

Twining vines, ± woody. Stems glabrous or with sparse adpressed or abundant spreading fine hairs. Leaves up to 25 cm; petiole 6-9 cm usually with spreading hairs; stipels 2-4 mm; leaflets thinly papery, inconspicuously finely hairy (rarely gla­brous) on both sides, lateral veins 5-7 pairs, gently curved; ter­minal leaflet elliptic, 9-14 × 4-8 cm, base rounded or ± cordate, apex shortly acuminate; lateral leaflets 9-12 × 5-7 cm, width ratio of abaxial to adaxial halves 1.5-2:1, base of abaxial half truncate, base of adaxial half rounded or slightly cuneate. Inflo­rescence axillary, 8-24 cm, with up to 6 nodes all in upper part, without flowers or scars in lower part; bracts usually persistent, broadly ovate, 2.5-4 × (0.7-)2-2.5 cm, both sides with dense fine usually adpressed short hairs; bracteoles caducous, up to 3 × 0.5 mm; pedicels 8-10 mm, with dense adpressed fine pale hairs. Calyx densely hairy; tube ca. 1 × 2 cm; lobes broadly triangular, laterals 4-6 × 4-6 mm, lowest (8-)12-14 × ca. 6 mm. Corolla white; standard 3-3.5 × 1.8-2 cm, ca. 1/2 length of keel or slightly longer; wings 5.5-6 × 0.8-1(-1.5) cm; keel equaling wings. Legume broadly oblong with rounded apex and base, 13-14 × 6-7 cm, 1.5-2 cm thick, leathery, with abundant reddish hairs and irritant bristles, both margins with a pair of wide ± flat wings 12-15 mm wide, both surfaces with 10-20 obliquely transverse erect crowded parallel lamellae completely concealing fruit surface, each divided into 2 wings along their margin with each wing flat or upcurved and up to 7 mm wide, lamellae all interrupted along midline of legume and not ex­tending into marginal wings of fruit. Seeds (2 or)3, reddish brown, with black striations and spots, reniform or almost dis­coid, ca. 3 × 2.5 cm, ca. 1.2 cm thick; hilum black, length slightly longer than 1/2 circumference of seed. Fl. Aug, fr. Oct.

Forest margins; 900-1100 m. Yunnan [Cambodia, Laos, Myan­mar, Thailand, Vietnam].

Mucuna interrupta is distinctive in its large fruit with flat marginal wings and wide lamellae uniformly interrupted along the midline, not extending into the winged margins, and with flat or upcurved apical halves. It is vegetatively almost identical to M. revoluta and M. hainan­ensis, which differ in the form of their fruit lamellae and usually have purple or reddish flowers.