Very locally common on the mid-slope of a gentle to moderately steep, 50-foot high, southwest-facing slope. Small (1/8-acre) degraded calcareous fen, in a heavily grazed pasture. Deep saturated marly muck, in a zone slightly elevated above the adjacent slope.
Associates include Carex sterilis, C. stricta, C. granularis, C. hysteracina, C. pellita, Glyceria striata, Schoenoplectus pungens, Eleocharis erythropoda, Lysimachia quadriflora, Solidago riddellii. Also locally abundant 1/4-mile to west on fairly large peat dome near the highway; here with Carex prairea, C. interior, Parnassia glauca.