United States, Illinois, Lake, Cedar Lake at Lake Villa. (NAD83/WGS84).
42.4222 -88.0898
T. 46N, R. 10E, Sect. 32
metros
789
Agressively spreading fully submerged plant, except for erect flowering spikes at the surface, and forms dense tangled beds, excluding other plants. Leaves in 4 whorls, each with 12 - 16 pairs of pinnae, weak and collapsing when pulled out of the water. Stems many branched at the surface, growing sideways, breaking and floating as roots develop, and then sink. Flowers pink, stamens in upper part of spike.