Perennial herbs, cushion-forming, glabrous; cushions dense, prickly. Rhizome branched, ascending. Stems ±erect, ±regularly forked, with proximal part densely covered with persisting wilted leaf bases. Leaves regularly and densely spirally inserted along stem; blade equal to or longer than sheath, terete, smooth, with apex acute, hard-pointed, prickly. Inflorescence reduced to a single lateral (axillary) subterminal flower with two scarious bracteoles; pedicel of variable length. Flowers unisexual or hermaphrodite (plants polygamous-dioecious or diclino-dioecious). Tepals glumaceous or papery with margins hyaline, lanceolate or ovate-lanceolate, often unequal. Staminate flower with 6 stamens shorter than or equalling tepals; anthers elongated, mucronate, much longer than the very short flattened ±triangular filament. Stigmas tapering. Capsule trilocular to triseptate, loculicidal to circumscissile. Seeds many, ovoid to pyriform; seed-coat distinct, forming inconspicuous appendage, whitish-yellowish, minutely reticulate, with cells slightly elongated longitudinally.