Herbs annual, 20-50 cm tall. Root gray-brown. Stem erect, usually much branched, terete; branches gray-green, sometimes light reddish, slightly compressed, subglabrous. Leaves sessile, gray-green, linear, terete, 0.5-1.5 cm × 1-1.5 mm, apex obtuse or subacute and with a bristle, bristle light yellow, ca. 3 mm. Glomerules axillary, usually 3-flowered, central flower larger, bisexual, lateral flowers female; bractlets ovate or ovate-lanceolate, margin slightly serrate, apex acuminate. Perianth segments abaxially with a longitudinal keel near apex and keel extending beyond apex as a longitudinal wing, abaxially slightly keeled in fruit, apex cucullate. Anthers broadly ovate to oblong, ca. 0.6 mm. Ovary narrowly ovoid, apex slightly concave; style obscure; stigmas 3, minute. Utricle enclosed by perianth; pericarp free from seed. Seed horizontal, vertical, or oblique, red-brown to black, sublustrous, subovoid, 0.8-1 mm, smooth, rim margin obtuse; radicle inferior. Fl. and fr. Jun-Sep.
Home