Mucuna subg. Macrocarpa

Jiang, Kaiwen, Huang, Yunfeng & Moura, Tânia M., 2020, Mucuna guangxiensis, a new species of Mucuna subg. Macrocarpa (Leguminosae-Papilionoideae) from China, Phytotaxa 433 (2), pp. 145-152 : 151

Key to the species of Mucuna subg. Macrocarpa :

1. Indumentum on the abaxial surface of the leaflets sericeous and usually dense but never red-brown..............................................2

- Indumentum on the abaxial surface of the leaflets absent or sparse or if dense then spreading and often red-brown ......................3

2. Flowers 6.5‒8.0 cm long; corolla greenish or yellowish white; legumes 22‒70 cm long, with 6‒15 seeds per pod M. guangxiensis

- Flowers 3.5‒4.5 cm long; corolla purple; legumes 13‒15 cm long, with up to 7 seed................................................. M. calophylla

3. Legumes with a pair of wings along both sutures .................................................................................................... M. birdwoodiana

- Legumes without wings along either suture.......................................................................................................................................4

4. Plant with latex; legumes with two sides parallel to each other, with an obtuse apex ..................................................... M. laticifera

- Plant without latex; legumes ± constricted between seeds, apex beaked...........................................................................................5

5. Leaflets with a dense, soft, pale, spreading but never ferruginous indumentum ............................................................. M. bodinieri

- Leaflets glabrous or sparsely hairy or with a ferruginous indumentum.............................................................................................6

6. Legumes with a thin epicarp, at least with irritant bristles on the outer surface, without irregular wrinkles ....................................7

- Legumes with a thick epicarp, without irritant bristles but densely with pubescent hairy (or turn glabrous with age) and irregular wrinkles on the outer surface..............................................................................................................................................................8

7. Leaves with a petiole 7‒16.5 cm long; leaflets glabrous or rarely with a sparse indumentum of stiff, pale hairs; legumes with both dense, short, fine red-brown hairs and sparse, caducous reddish brown bristles on the outer surface ..................... M. sempervirens

- Leaves with a petiole 4‒6.5 cm long; leaflets glabrous; legumes with only a few irritant bristles.............................. M. kawakabuti

8. Corolla bi-colored, with standard greenish or pinkish white, wings dark purple, keel lighter mauve or yellowish green; legumes with margins often markedly constricted between seeds ............................................................................................ M. macrocarpa

- Corolla greenish white; legumes with margins not or slightly constricted between seeds .......................................... M. thailandica