Fls hermaphrodite, often strongly protandrous (? unisexual), axillary, solitary or in clusters, subtended by bracteoles and lfy bracts. Calyx-lobes 4-2, free; petals 4-2, cucullate; stamens caducous, 4, or 8 in two whorls, filaments short, anthers broad-linear; ovary 4- to 1-celled, styles 4-2, short, stigmas papillose or plumose; fr. small, ind., often winged or ribbed, sts woody, crowned by persistent calyx-lobes. Us. perennial herbs, sts partly woody; lvs opp. or alt. orbicular to lanceolate, entire, toothed, or lobed. About 70 spp.; Southern Hemisphere and extending to S. E. Asia; in N.Z. on banks and disturbed areas, gumlands and peat. Of the 7 N.Z. spp. probably all but one are endemic.

Annual or perennial herbs or subshrubs with a simple taproot or a horizontal stolon system, glabrous, pilose or scabrous. Stems prostrate, decumbent to erect, terete or 4-5-ribbed, sometimes rooting at the base. Lvs alternate or opposite, terete to ovate, usually toothed to pinnatifid, less commonly entire. Hydathodes 0. Infl. spike-like, of (1)-3-7-flowered dichasial cymes in the axils of alternate primary, leaflike bracts. Secondary and tertiary bracts linear, membranous. Fls usually ☿, 2-4-merous; pedicels short. Sepals deltoid, persistent and accrescent. Petals ± clawed, hooded. Stamens twice as many as or rarely as many as sepals; filaments short; anthers broadly linear. Ovary 2-4-celled. Styles 2-4; stigmas capitate or fimbriate. Fr. indehiscent, sometimes winged between sepals, smooth or tuberculate between ribs or wings; septa and endocarp woody; exocarp membranous to ± fleshy. Seeds 1-4.