Erect or ascending annual herb to c. 50 cm high; stems simple, or usually, many-branched, with scattered fine, semi-appressed to spreading bristles. Leaves mostly opposite toward base, but alternate in upper parts of the plant; petiole 7–25 mm long, shortly bristly; blade usually narrowly to broadly elliptic, c. 15–80 mm long, 5–32 mm wide, margins coarsely and irregularly crenate-dentate, recurved to flat, apex acute to obtuse, surfaces strigose; leaves surrounding cyathia similar to sterile leaves but usually smaller. Cyathia clustered, often head-like at tips of branchlets; peduncles 0.5–1 mm long; involucre cylindric, 2.5–3 mm long, glabrous, divided into 5–7 linear, papillate lobes; gland 1, c. 1 mm long, oblong, lacking appendages; female flowers with styles c. 1 mm long, bifid from half way or nearer base. Capsule broadly ovoid, c. 3 mm long, 4.5 mm diam., glabrous; seeds ovoid, angular in cross-section, c. 2.5–3 mm long, grey, brown or blackish, with low tubercles irregularly arranged or in transverse rows; caruncle c. 0.5 mm long. Flowers mostly Jan–Apr.
MuM, CVU, HNF. Also naturalised Qld, NSW, S. America, Eurasia. Native to southwestern North America and Mexico. Currently known only from recent (2020, 2021) collections from beside the Hume Freeway between Wallan and Broadford where locally abundant and undoubtedly established there for several seasons prior to its first collection.
