Spinyhead sida

Perennial shrub to 1.5 m high, slender, erect or spreading, fibrous to woody, stems with fine stellate hairs.

Leaves narrow-lanceolate, 2–9 cm long, 5–40 mm wide, glabrous or wiith fine hairs on margins, crenate; stipules of unequal length.

Flowers solitary or occasionally in crowded heads in the leaf axils. Corolla 6–9 mm long, yellow. Calyx 6 mm long, acuminate.

Fruit 3–5 mm diam.; mericarps 5–8, wedge-shaped and deeply indented on both sides, rounded on back, with 2 sharp awns.