Herbs, perennial. Taproots often stout. Stems prostrate, much-branched proximally, terete to angular. Leaves opposite, not connate, connected by thickened margins from which stipules arise, sessile; stipules 2 per node, silvery, lanceolate to ovate, margins entire to irregularly fimbriate, apex 2-lobed; blade prominently 1-veined, needlelike, not succulent, apex spinose. Inflorescences axillary, 1–3-flowered clusters; bracts paired, resembling stipules, smaller. Flowers sessile; hypanthium cup-shaped, not abruptly expanded distally; sepals 5, distinct, olive-green, oblong to obovate, 1.2–2.8 mm (excluding awns), indurate, herbaceous, margins whitish, scarious, apex spinose, prominently hooded, awned, hoods projecting inward and enclosing developing fruit, awns arising from near apex, widely divergent, very stout, spinose, 3 awns and associated sepals well developed, alternating with 2 reduced sepals; nectaries not apparent; stamens 3–5; filaments distinct to base; staminodes 5, adnate basally with alternating filaments, ovate-triangular, apex acuminate; styles 2, distinct, subcapitate, 0.2 mm, glabrous proximally; stigmas 2, subterminal, obscurely papillate (50×). Utricles ellipsoid to cylindric, teeth absent, indehiscent. Seeds tan with red spot at hilum, narrowly ovate, not compressed, smooth, marginal wing absent, appendage absent; embryo peripheral, straight to slightly curved.
Coastal w North America, South America (Chile, Ecuador, Peru).
Species 6 (1 in the flora).