Annual or perennial herbs. Stems generally long creeping and rooting at the nodes. Leaves hairy, sometimes with glandular hairs to subglabrous, oblong-ovate or lanceolate, entire. Ochreae cylindrical, truncate or with terminal fringes or bristles. Flowers arranged in globose heads or spikes. Perianth 4-5 lobed, often coloured. Stamens 5-8, dilated at the base. Styles 2-3, often connate below. Achene lenticular, trigonous or biconvex.