Herbs, annual, erect to spreading, 5-40 cm tall. Rootstock absent, taproot slender. Stem 2-3 mm thick, branched from all but lowest nodes, smooth and glabrous. Leaves opposite; stipules absent; petiole absent; leaf blade linear to oblong-elliptic, (1.2-)2.5-4 × 0.4-0.6 cm, base cuneate, margin entire, apex acute. Inflorescence mostly a dichotomous cyme, sometimes initially 3-or 4-branched; primary involucral leaves 2, similar to normal leaves, primary rays 2, to 5 cm, often much shorter; cyathophylls 2, similar to normal leaves, but smaller. Cyathium shortly stipitate; involucre narrowly campanulate, 1-2 × 1-1.5 mm, lobes subtriangular; glands 4, pale yellow, crescent-shaped, apex long 2-horned, bent outside. Male flowers many, exserted from involucre. Female flower: ovary pedicel 3-5 mm, exserted from cup; ovary smooth, glabrous; styles free; style arms 2-lobed. Capsule trigonous-ovoid-globose, ca. 3 × 3 mm, smooth or very finely reticulate, glabrous. Seeds angular-terete, ca. 2.5 × 2 mm, black or gray-brown, irregularly punctate-papillate; caruncle slightly peltate, white, stipe very short, appearing sessile. Fl. and fr. Jun-Jul.
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