Tetragonolobus Scop.

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1981, Flora Europaea. Volume 2. Rosaceae to Umbelliferae, Cambridge University Press : 176-177

60. Tetragonolobus Scop. 1

Like Lotus but leaves 3-foliolate; stipules herbaceous; flowers solitary or paired; calyx-teeth equal; legume almost square in transverse section, with the angles winged or keeled.

1 Peduncles at least twice as long as the leaves; calyx-teeth shorter than tube; corolla yellow or orange

2 Flowers solitary; corolla 25-30 mm; legume 30-60x 3-5 mm, glabrous or subglabrous 1. maritimus

2 Flowers 1-4 on each peduncle; corolla 17-25 mm; legume 20-40 x 4-6 mm, pubescent 2. biflorus

1 Peduncles shorter than or equalling leaves; calyx-teeth longer than tube; corolla pink, red or purple

3 Legume with 4 wings at least 2 mm wide; calyx-teeth not more than twice as long as tube; style not membranous-winged at the tip 3. purpureus

3 Legume with wings less than 2 mm wide, often only keeled;

calyx-teeth 2-3 times as long as tube; style with a unilateral membranous wing at the tip 4 Legume 4-winged or -keeled; seeds 3-5 mm in diameter

4. conjugatus 4 Legume with 2 wings on the upper side but neither winged nor keeled beneath; seeds 2-2-5 mm in diameter 5. requienii