Erect slender annual, to 30 (–40) cm high, often several-branched from base, glabrous, or with a few cottony hairs on new growth and axils. Leaves oblong to narrowly obovate, 8–25 mm long, 2–7 mm wide, serrate. Inflorescences axillary, racemose, of (1–) 2–4 capitula, the lowest capitulum usually sessile or subsessile, and the upper 1–3 with peduncles to c. 5 mm long. Capitula hemispherical to biconvex, 2–4.5 mm diam.; involucral bracts spathulate to obovate, 1–1.5 mm long; receptacle convex. Female florets c. 100–170 in 3–5 rows; corolla 0.2–0.3 mm long. Bisexual florets (4–) 10–18; corolla c. 0.6–0.8 mm long. Fruiting heads readily disintegrating; bracts widely spreading; receptacle 1–1.5 mm diam., with a pith layer contained entirely or nearly within the dome. Achenes obloid, narrowly obovoid, or narrowly cuneoid, 0.8–1.1 (–1.3) mm long, at least 3 times as long as wide, obtuse or rounded (female florets) or truncate (bisexual florets) at apex, finely 2–4-ribbed; ribs with short appressed hairs, sometimes inrolled at apex; pericarp thickened and spongy in distal 25%.
Occurs in moist sandy, silty or clay soils (rarely in rock crevices) at margins of waterholes, dams and creek lines, and on floodout and gilgai landforms.
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