Calthea palustrus. North American, native, perennial wildflower with buttercup yellow flowers. Leaves are edible when cooked and flower buds can be cooked and pickled as a caper subsitute. Good beside streams, ponds or any moist area. Grows 6-12" tall by 12-24" wide. Blooms April to May. Full sun to part shade. Plant in rich, constantly moist soil. Zones 2-9.