Featherfoil is an aquatic herb, annual or perennial, with a submerged stem and fibrous roots. The leaves are submerged to floating; alternate, opposite or whorled; pinnately or bipinnately divided; linear or filiform. The inflorescence stalks are a partially immersed, floating cluster; each stalk spongy-inflated. The inflorescence is a series of whorled, sessile umbels occurring where stalk becomes constricted. Flowers are numerous, white, yellow, or violet. The fruit is a rounded capsule containing numerous, tiny, brown seeds.
