Submerged herb, monoecious; root absent forming a much branched tengled mass; branchlets brittle, slender green; leaves 4-9 in a whorl, dichotomously forked with 2-4 filiform, minutely dentate, segments, bright or olive green, robust, rigid, brittle; stipules absent; flowers axillary, solitary, minute, sessile; male flowers and female flowers are produced in separate axils of same plant; male tepals 6-12, narrow or linear, greenish white, ciliate at apex, sub clavate, 2-fid; stamens 20-30 in whorls, filaments short, anthers exserted; connective prolonged at the tip into 2 spines and a central projection; pistillode absent; female perianth as in males; ovary sessile, superior, ovoid 1-locular; ovule solitary, pendulous; style subulate, oblique, stigmatic on one side; fruit a nutlet, ellipsoid or ovoid, laterally compressed, terminating in minutely tuberculate, apical spine, straight or slightly recurved.