Herbs, perennial, sometimes suffrutescent, 7-12(-25) dm; roots not also arising from proximal nodes; rhizomes present. Stems ribbed, glabrous or densely pubescent. Leaves: ocrea reddish brown, cylindric, 10-40 mm, base inflated, surface glabrous or densely pubescent; petiole 0.3-2(-3) cm, glabrous or densely pubescent; blade (7.5-)9-22(-27) × 2.8-7.8 cm, base cordate to truncate, margins ciliate, apex acuminate to caudate-acuminate, faces pubescent abaxially, glabrous or pubescent adaxially. Inflorescences 40-110 × 10-55 mm; peduncle 10-80 mm, glabrous or pubescent; ocreolae not overlapping, margins eciliate. Pedicels ascending to spreading, 1-4 mm, glabrous. Flowers 3-9 per ocreate fascicle; perianth white or pinkish, often with scattered reddish glands, glabrous, nonaccrescent; tepals oblong to obovate, dimorphic, outer 3 larger than inner 2, 2.2-3.8 mm, margins entire, apex obtuse to rounded; filaments inserted at bases of tepals, distinct, glabrous; anthers red to purple, ovate; styles distinct. Achenes included, brown, 3-gonous, 2.1-2.5 × 1.3-1.8 mm, dull, minutely roughened. 2n = 22.

Flowering Aug-Oct. Moist disturbed places, marshes; 0-500 m; introduced; St. Pierre and Miquelon; B.C.; Calif., Mass., Oreg.; Asia (Bhutan, China, India, Nepal, Tibet).