Herbs, perennial, erect, to 0.55 m tall. Rhizomes slender, reddish. Stems 4-angled, glabrous and smooth except puberulent to hispidulous at nodes. Leaves in whorls of 4, sessile; blade drying papery, linear or linear-lanceolate, 27-40 × 3-9 mm, glabrous or antrorsely scabrous along midrib and margins, base obtuse to rounded, apex narrowed then shortly obtuse; principal vein 1, with 2 weaker lateral veins reticulating near middle of blade. Inflorescences terminal, paniculate, many flowered, 2-15 cm; peduncles glabrous or scabrous; bracts few, oblanceolate, 1-2 mm; pedicels 1-4 mm. Ovary ellipsoid and laterally flattened, ca. 1 mm. Corolla whitish, rotate, 4-5 mm in diam.; lobes 4(or 5), elliptic to lanceolate, acute or mucronulate. Mericarps ellipsoid, at least 2 mm, glabrous or with ± sparse hooked trichomes ca. 0.3 mm. Fl. Jul-Aug, fr. Aug-Sep.
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