Plants glabrous. Stems leafy, creeping or floating, not bulbous-based, without bulbils. Roots nodal, never tuberous. Leaves cauline, simple, petiolate; blade undivided or 3-lobed, much longer than wide, margins entire. Inflorescences axillary, solitary flowers. Flowers pedicellate (pedicels naked or leafy); sepals deciduous soon after anthesis, 3; petals 7-11, white or reddish; nectary scale attached on 3 sides for at least half its length, forming pocket (sometimes mouth of pocket prolonged as short flap), glabrous, free margin entire; style present. Fruits achenes, 1-locular, 4.2-5.2 mm; achene body oblong-lenticular, 1.3-1.7 times as wide as thick, prolonged beyond seed as corky distal appendage; wall thick, smooth; margin low corky band; beak much shorter than achene body.

Species 1 (1 in the flora): North America, Eurasia.