Annual, puberulent or slightly mealy, up to 1 m. Stems thin, twining or spreading, angular. Leaves 2-6 cm. long, cordate-sagittate, acuminate; petiole almost as long as blade. Flowers in narrow paniculate, axillary spike-like inflorescences. Pedicels 2-3 mm. long, articulate above middle. Perianth-segments 2-2.5 mm., greenish-white, the outer ones somewhat larger, keeled or slightly winged in fruit. Stamens 8. Achene 4-5 mm. but not protruding, black, granulate. Fl. April- July.