Stems are moderately elongate, relatively stout, partially submersed
but with a considerable portion of the leafy branches erect. Leaves are
pinnately dissected, all whorled, stiffish, usually with 20 or more linear-filiform
divisions, the upper divisions 4-8 mm long, the lower divisions much reduced,
appearing featherlike, grayish green. Emersed leaves are usually 2.4-5
cm long, the divisions to 8 mm long, petiole 5-7 mm long. Flowers in North
America are all female, white, in the axils of essentially unreduced leaves.
This species grows rooted in the substrate with part of the plant beneath
the surface of the water and a portion of the nonflowering stem emersed.
Plants do not form turions. This species forms creeping rhizomes that
may give rise to multiple stems. Stems branch and root at the nodes allowing
for formation of fragments.
Plants grow in sluggish waters, edges of streams, lakes, ponds, drainage
and irrigation ditches, and canals, backwaters, sloughs and lagoons. Populations
may be quite dense, sometimes as floating mats that have been uprooted,
often choking waterways and impeding navigation.