Herbs , young vegetative parts often with rust-colored pubescence, barely mucilaginous. Leaves submersed and floating; petiole short to long. Submersed leaves: blade in 3-7 dichotomously [trichotomously] branched, linear segments. Floating leaves: blade terminal, linear-elliptic [broadly elliptic], margins entire or notched at base, appearing only during flowering, inconspicuous [more evident in C . aquatica , a tropical species]. Flowers: sepals 3, petaloid, obovate; petals 3, oval, with proximal, yellow, nectar-bearing auricles, base clawed; stamens 3-6, opposite petals; pistils [1-]2-4, simple, 1-locular; ovules [1-]3[-5]; stigma capitate. Fruits elongate-pyriform, tapered to apex. Seeds ovoid [somewhat globose], tuberculate. x = 13.
Sep and pet similar, both petaloid; stamens 3-6; anthers extrorse; pistils 3-6; principal lvs opposite, palmately finely dissected, submersed; some small, alternate lvs with floating, entire, peltate blade usually also present. 7, New World.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.