Perennial herbs, erect, glabrous. Leaves 1–2 (–3) cauline; sterile shoots with 1–3 (–5) cauliform terete leaves; pith parenchymatous; cataphylls distinctly developed; stomatal lines distributed evenly. Flower bracts 1–2, short, membranous. Flowers borne singly, terminal, large, usually 10–40 mm long; tepals linear-lanceolate, acuminate, pale. Stamens 6; anthers linear, longer than filaments; connective with or without apical projection. Ovary sessile. Style with 3 ±tapering stigmas. Capsule oblong-trigonous or ellipsoid-trigonous, acuminate, imperfectly triseptate, with upper part recurved after dehiscence. Seeds many; seed-coat forming two long tail-like appendages.