Global description
Rhynchosia malacophylla is a perennial herbaceous plant, glabrous to slightly pubescent, creeping or climbing, that can measure 3m long. The leaves are alternate, compound trifoliate, with oval-rhombic leaflets, sparsely covered with golden glands on the underside. The loose inflorescence includes a dozen yellow flowers. The fruit is an oblong-oval pod covered with a thin and glandular pubescence. The seed is kidney shape and marbled.
General habit
Perennial herbaceous plant, rather glabrous, trailing or climbing, reaching 3 meters long.
Underground system
Plant has a taproot system.
Stem
The stem is hairy in the Mascarene but not viscous. In other geographic areas, it can be glabrous.
Leaf
The leaves are alternate, compound trifoliate, 4-16 cm long. The base of the petiole is framed by two narrow stipules, ovate-triangular, 3 to 5 mm long, which are deciduous. The ovate-rhombic leaflets with obtuse to slightly acuminate apex, are 1 to 4.5 cm long (up to 6.5 cm) and 1 to 5.5 cm wide. The two sides are slightly hairy or glabrous. The lower surface is studded with golden color glands. The margin is densely covered with short stiff hairs. The two lateral leaflets are very unequal.
Inflorescence
The flowers are grouped by 6 to 12 in a loose inflorescence, 5 to 23 cm long. The oval, narrow bracts measure 1.5 to 2 mm long.
Flower
The yellow flower is papilionaceous type. It measures 1.5 cm long. The pedicel measures 1.5 to 3 mm long. The calyx (3.5 to 7 mm) is covered with a dense pubescence. The standard, obovate circular (8-14 mm long), yellow in color, sometimes streaked with red, is pubescent and glandular. The lower narrow lobe is the longest.
Fruit
The fruit is an oblong-obovate pod of 15 to 20 mm long and 4.5 to 7 mm wide, with rounded end and tapering base, covered with fine glandular hairs.
Seed
Seed, round, kidney-shaped, 4.5 mm long, 3 mm wide and 2 mm thick. Its integument is marbled.