Much like no. 1 [Pilea pumila (L.) A. Gray], the herbage less pellucid; achenes dark purple or dark olivaceous to nearly black, pale-margined, irregularly elevated on the sides, broadly ovate, 1.3–2 mm, 70–85% as wide; seed tuberculate. Wet, boggy or springy soil; P.E.I. to Minn. and N.D., s. to Va., Ind., and Nebr.; Fla. July–Sept. (P. opaca)