Plants 1-3 dm; blades of basal lvs ovate to oblong, 1-3.5 cm, 1/2 to 3/4 as wide, narrowed at the base and decurrent on the petiole; cauline lf usually present, erect, lanceolate to ovate, 3-15 mm, narrowed to a sessile base; pet 5-13-nerved, 6-10 mm, 1/5 to 1/2 longer than the green sep; staminodes green or yellow, 3.5-5 mm, dilated to an obovate or reverse-triangular scale with (5)7(9) short filaments on the distal margin; 2n=36. Calcareous shores and wet meadows; Lab. to B.C., s. to Que., Ont., Mich., Wis., S.D., and N.M. June-Aug. Perhaps better as P. palustris var. parviflora (DC) B. Boivin.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.