1. Pedicel erect, to 3 cm, terete, striate.

2. Branches and twigs terete ; flowers pale yellow.

3. Tubers basal, stems fleshy, terete , buried in sandy soil, 40-160cm tall, simple, thicker in the lower part.

4. Current year branchlets terete; leaf blade oblong, 9-12 cm, base rounded, apex acute.

5. Stems pendulous, terete, many-noded.

6. Stems erect or twining, 4-ribbed at first, later terete, usually tuberculate and with longitudinally lengthened lenticels.

7. Leaves alternate, sessile, terete, fleshy, base expanded, apex obtuse or aristate awned; leaf axil fascicular pilose.

8. Shrubs or small trees to 8 m. Branchlets terete, puberulent when young, glabrescent.

9. Description: Perennial herbs, 5-20 cm tall, densely white villose; roots slender, terete , up to 40 cm long, fleshy, stem buried in sand with apical part emerged above ground.