Acanthospermum Schrank

2 species naturalized Aust.; Qld, NSW, NT

*Acanthospermum australe (Loefl.) Kuntze

Prostrate herb with stems up to 60 cm long. Leaves opposite, petiolate, ovate to rhomboidal, 15–20 mm long, 1 cm wide, serrate or crenate towards the tip. Heads solitary on short axillary leafy branches. Involucral bracts in 2 rows; the outer of 5 (up to 8) simple bracts 1–2 mm long; the inner row of 6 (up to 8) bracts up to 10 mm long, enclosing the fruits of the ray florets at maturity; the bracts becoming spinescent with hooked spines. Ray florets bisexual. Disc florets sterile. Cypsela enclosed by a spiny bract. Coast. Weed of waste places. Introd. from America. Fl. summer