Prostrate to (rarely) erect annual or facultative perennial, spreading to c. 25 cm diam. and/or 20 cm high, rarely rooting from lower nodes; branches glabrescent to moderately cottony, if glabrescent then axils and young growing tips usually with some cottony hairs. Leaves ± kite-shaped, 3–12 (–27) mm long, 1.5–6(–11) mm wide, variably serrate to shallowly incised; surfaces glabrescent to densely cottony, with scattered resin droplets. Capitula hemispherical to subglobular at anthesis, 1.5–3(–3.5) mm diam., solitary, sessile or subsessile; involucral bracts obovate with erose membranous margins, c. 1 mm long; receptacle depressed-hemispherical; female florets 75–200, corollas 0.1–0.25 mm long; bisexual florets 10–20, corollas 0.3–0.4 mm long. Fruiting heads breaking up before stems senesce. Cypselas narrowly obcuneate, 0.7–1.1 mm long; ribs 4(–6) with short ascending bristles; intervening faces with scattered vesicular hairs; apex truncate or obtusely rimmed, forming a pale, pithy portion up to a half the cypsela length, very slightly impressed. Flowers Sep.–Feb.
MuM, Wim, VVP, VRiv, MSB, RobP, MuF, GipP, Gold, CVU, GGr, DunT, NIS, EGL, HSF. Occurs in all Australian States. Widespread through south-east Asia and the Pacific, e.g. India, Russia, China, Vietnam, Japan, Philippines, Indonesia, Papua New Guinea, New Caledonia, New Zealand. Scattered throughout the State on muds, clays and sands surrounding lakes, dams, billabongs, watercourses, or their drying beds. It is occasionally a weed of agricultural land.
The extreme measurements derive from plants growing in permanently moist, shaded sites, or rarely, from wholly submerged plants.
Plants from the sandy mallee areas of north-west Victoria can be moderately cottony. The name Centipeda minima var. lanuginosa has been applied to cottony plants of C. minima and C. nidiformis. However, indumentum density varies continuously in this species from being virtually non-existent to moderately cottony and consequently a clear demarcation in indumentum density that could define this taxon is lacking (Walsh 2001).
