Herbs, annual or perennial. Stems ascending, decumbent, prostrate, or erect. Leaves opposite, sessile or petiolate; blade ovate to obovate, not fleshy, margins entire, long-pilose abaxially and sometimes adaxially. Inflorescences terminal and/or axillary, sessile, subglobose heads, often subtended by involucres of sessile leaves; bracts and bracteoles thin. Flowers bisexual; tepals 5, connate proximally; stamens 5; filaments connate basally into tube; pseudostaminodes absent; ovule 1; style 1, 1.5-4 mm; stigmas 2(-3), subulate or filiform. Utricles included in tepals, stramineous, ovoid or oblong, somewhat compressed, membranous, usually indehiscent. Seeds 1, lenticular, subglobose, to ovoid, smooth.