The Gardeners Dictionary (fourth edition) 1: 28. 1754.

Etymology: Greek, ancient name
Synonyms: Machaerocarpus Small
Treatment appears in FNA Volume 22.

Plants perennial, floating-leaved or emersed, glabrous; rhizomes usually absent; stolons absent; corms present; tubers absent. Roots not septate. Leaves: petiole triangular; blade with translucent markings absent, narrow-lanceolate to ovate, base rounded to attenuate, basal lobes absent, margins entire, apex acute. Inflorescences racemes [panicles], of 1–9 whorls, erect, emersed; bracts coarse, apex acute, surfaces smooth. Flowers bisexual, pedicellate; bracts subtending pedicels, lanceolate to ovate-lanceolate, much shorter than pedicels, apex acuminate; pedicels ascending to spreading; receptacle flat; sepals erect, without sculpturing, herbaceous; petals white or pink, erose; stamens 6; filaments dilated, glabrous; pistils 6–15, in single ring, radiating in starlike pattern, weakly coherent proximally; ovules 1–2; styles terminal. Fruits longitudinally ribbed, laterally compressed, not abaxially keeled, abaxial wings absent, lateral wings absent, glands absent. x = 7.


North America, Europe, Australia.


Species 5 (1 in the flora).