Annual or perennial herbs. Stems erect or procumbent, strongly branched; hairs glandular or eglandular. Leaves simple, opposite below, then alternate, entire or coarsely dentate, pungent-pointed, hairs glandular or eglandular. Inflorescences axillary or terminal, solitary or in small clusters. Capitula sessile, heterogamous; involucral bracts uniseriate, involute, partially enclosing ray achenes; receptacle with persistent scales subtending each disc floret. Ray florets equal in number to involucral bracts, female, ligulate, yellow. Disc florets many, male or bisexual; corolla yellow; anther tips ovate; style branches with short apical appendages. Ray achenes 3-angled, beaked, with pappus absent; disc achenes cylindrical or obconical, with pappus present (not in Australia) or absent.
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