United States, Wisconsin, Barron, Horseshoe Lake. Polk/Barron Counties [Barron Co. from Lat./Long.]
45.45116° N, 92.15524° W; T34N R14W sec07
Located floating or just under the surface in sheltered areas. Common assoc.: (Brasenia schreberi) watershield, (Nymphaea odorata) white water lily, (Nuphar variegata) spatterdock, (Pontederia cordata) pickerelweed, (Lemna minor) small duckweed,
Restricted to north-central bay and "Mud Lake". Uncommon, scattered individuals occur interspersed between the lilypads.