Ranunculus macounii Britton
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Much like no. 5 [Ranunculus pensylvanicus L.f.], but sometimes glabrous, the stems widely branched and sometimes rooting from the lower nodes; pet 3.5–5 mm, equaling or commonly longer than the sep; fruiting heads mostly 7–12 mm, ovoid-cylindric; achenes 2.7–3.3 mm; beak triangular- subulate, 0.8–1.8 mm; 2n=32. Marshes and wet meadows; Lab. to Alas. and e. Asia, s. to Que., n. Mich., Io., and Ariz. June–Aug.