Herbs annual, often tinged purple-red, usually appearing conic, 10-40 cm tall, glabrous. Stem erect, terete or with colored ribs, glabrous or slightly glandular pubescent, much branched. Petiole short; leaf blade linear to narrowly lanceolate, to 7 × 1 cm, base attenuate, merging into petiole, margin entire to indistinctly erose-dentate, apex acute to acuminate; midvein yellow-white. Compound dichasia borne in leaf axils from near base of plant and on upper part of branches, apical branchlets of inflorescence acicular. Flowers not pedunculate, bisexual. Perianth segments 5, spreading in fruit, narrowly elliptic, slightly fleshy abaxially, margin membranous, apex obtuse or abruptly acute. Utricle depressed, orbicular; pericarp pellucid, adnate to seed. Seed horizontal, depressed, ca. 1 mm in diam., rim margin truncate or with a rib. Fl. Aug-Sep, fr. Oct.