Herbs, perennial or rarely annual. Roots thin, rarely tuberous. Leaves spirally arranged or 2-ranked; blade sessile. Inflorescences terminal and/or axillary, cyme pairs (often aggregated into larger spikelike or paniclelike units), cymes sessile, umbel-like, contracted, subtended by bracts; bracts inconspicuous, less than 1 cm; spathaceous bracts absent; bracteoles persistent. Flowers bisexual (bisexual and pistillate in C. repens), radially symmetric; pedicels very short or well developed; sepals distinct, subequal; petals distinct, white or pink to rose [rarely blue], equal, not clawed; stamens 6 or 0--3, all fertile, equal; filaments glabrous or bearded; ovary 2--3-locular, ovules [1--]2 per locule, 1-seriate. Capsules 2--3-valved, 2--3-locular. Seeds [1-]2 per locule; hilum punctiform; embryotega abaxial. x = 6--8.