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Herbs, without stinging hairs. Stems ascending. Leaves alternate or opposite; stipules persistent, lateral, free; leaf blade ovate, 3-veined or triplinerved, margin serrate; cystoliths punctate. Inflorescences axillary, androgynous (plants monoecious), sessile, glomerules crowded on broad, campanulate, dentate involucre. Male flowers numerous on margin of the involucre; perianth lobe 1, often split and unequally 3-lobed or 3-toothed; stamen 1; rudimentary ovary absent. Female flowers 1 or 2, in center of involucre; perianth absent; staminodes absent. Ovary straight; stigma filiform, papillose-hispid, almost persistent; ovule orthotropous. Achene compressed ovoid, woolly or glabrous, enclosed by involucre. Seeds with endosperm; cotyledons elliptic.
Inflorescences of sessile clusters in the leaf axils; clusters either bisexual with few-many flowers surrounded by a common campanulate involucrum of fused bracts or inflorescence clusters of many very small involucres each with 1(2) female flowers (the involucres then appear as perianths).
Female flowers naked, pedicellate, consisting of an ovary covered with a woolly tomentum; stigma sessile, filiform; staminodes absent Entirely-female involucres are common on certain individuals, and then much smaller and with much fewer flowers than the bisexual involucres.
Slender annual or perennial herbs, occasionally subshrubs, with erect or prostrate stems, monoecious or apparently dioecious (by abortion of all bisexual inflorescences leaving only female flowers).
Male flowers pedicellate, club-shaped; perianth 3-lobed, one lobe apiculate and provided with prominent bristles; stamen 1, inflexed in bud, later reflexed; rudimentary ovary absent.
Bisexual involucres usually with many male flowers and 1-few female flowers (occasionally all the flowers are male); bracts and flowers with long woolly hairs.
Achene enclosed in the persistent involucre, brown, shiny, often crowned by the persistent stigma.
Leaves alternate or opposite, petiolate, serrate; stipules lateral, free.
Cystoliths dot-like.
