Herbs, perennial, biennial, or annual, synoecious (subg. Rumex and Platypodium) or dioecious (subg. Acetosa and Acetosella), occasionally polygamomonoecious, with taproots and usually short caudex, or sometimes rhizomatous and/or stoloniferous. Stems erect, ascending, or prostrate, glabrous or papillose-pubescent. Leaves basal (in some species) and cauline, alternate, petiolate; ocrea persistent or partially deciduous, membranous; petioles present on basal and proximal cauline leaves, absent on distal cauline leaves, bases not articulated; blades variable in shape, basal (if present) and proximal cauline leaves from broadly ovate or almost orbiculate to linear, becoming progressively smaller and narrower distally, margins entire (or basally lobate), flat, or occasionally undulate or crisped. Inflorescences terminal, sometimes terminal and axillary, paniclelike, rarely simple. Pedicels present. Flowers bisexual or unisexual, (1-)4-30 per ocreate fascicle, base stipelike; perianth green, pinkish, or red, campanulate, glabrous; tepals (5-)6, connate proximally, sepaloid, dimorphic, outer 3 remaining small, inner 3 usually enlarging, sometimes 1-3 with central vein transformed into tuberculate callosity (tubercle); stamens 6; filaments distinct, free, glabrous; anthers, yellow to brownish yellow, ovate to elongate; styles 3, spreading or reflexed, distinct; stigmas 3, fimbriate or plumose. Achenes included in accrescent and usually veiny perianth, tan to dark brown, unwinged to weakly winged, 3-gonous, sometimes compressed-3-gonous or nearly pyramidal, glabrous. Seeds: embryo straight. x = 7, 8, 9, 10 (polyploidy widespread in the genus).