or perennial, scapigerous marsh herbs, monoecious. Leaves simple, rosulate or
cauline, base sheathing. Inflorescence of involucral head, peduncles few to
many, enclosed in basal sheath. Flowers unisexual, male or female mixed, or
male in middle, female marginally. Male flowers: sepals 2 or 3, petals 2 or 3. Stamens 4 or 6, inserted at
corolla-base. Female flowers: sessile or stipitate, sepals 1-3, petals 0-3,
free. Ovary superior, usually 3-, rarely 2-locular. Fruit a 3-celled,
loculicidal capsule. Seeds 2 or 3,
smooth, striated, or ribbed.