Rhizomatous plant 70-100 cm. Leaves linear, 50-80 cm x 4 mm. Flowering shoot with 2-3 flowers on short pedicels bears 3 small leaves. Flowers violet or white, 5-7 cm diam. V - mid spring to late autumn, in St. Petersburg April-October. Fl - June for 2-3 weeks. Fr - August. Shade-tolerant.

European part of the FSU, Caucasus, western Siberia, Sayans and central Europe. In clearings and forest margins and in meadows.

A closely related species is I. sanguinea Donn, occurring in Siberia, the Primorskiy region of the Far East, Mongolia, Japan and northeastern China. It differs in its more coriaceous leaves and broad perianth lobes.