Annual, simple or with rather few long branches from below, 12-50 cm. Leaves ovate or triangular, to 8 x 7.5 cm, coarsely dentate, acute to acuminate. Monoecious or dioecious. Inflorescences 2 in each leaf axil. Upper or all inflorescences male, narrow and elongate, to c. 13 cm, straight or ± curved, longer than leaves; axis compressed and 2-winged with flowers on upper surface only. Lower or all inflorescences female, shorter and often denser, shorter than leaves, axis not compressed; inner pair of perianth segments accrescent in fruit, ovate, 1.5 mm, pilose over entire surface. Fl. 3-4. Waste ground, limestone cliffs & rocks, 10-30 m.
S. Europe, N. Africa, S.W. Asia.