Stout, rhizomatous perennial to 12 dm; lower lvs subrotund, 2–3 dm long and wide, broadly rounded above, broadly cordate at base; cauline lvs much smaller; mature pedicels visibly jointed near the base; valves cordate-ovate, 3–5 mm, without grains; 2n=20. Native of Europe, sparingly naturalized in the ne. part of our range.
A herb. It keeps growing from year to year. It grows 1 m tall. It forms thick patches. The leaves are heart shaped and can be 40 cm wide. It has a dense spike of flowers.