Ozark Plateau: Boston mountains: Valley of the Buffalo River: dense deciduous woods with large cliffs and boulders of limestone in narrow, deeply-entrenched valley of Clark Creek (""Lost Valley""),
Hay county: San Marcos River, San Marcos. Attached plants growing in about three feet of water and flowering submersed. Floating plants flowering emersed.
Sattrup Mose, bog 10 Km N of Horsens. In marginal field together with Arabidopsis thaliana, Geranium molle, G. pusillum, Holcus lanatus, Myosotis arvensis and Festuca pratense.