Lactuca serriola

Annual or biennial, 1–2 m high; stems stiffly erect, usually unbranched below inflorescence. Leaves glaucous, margins and midrib shortly spiny; basal and lower cauline leaves sessile, c. oblanceolate to oblong, 3–18 cm long, 2–6 cm wide, entire to pinnatisect, spreading but lamina often near-vertical; upper cauline leaves similar but smaller, bract-like at inflorescences. Capitula pedunculate, solitary, axillary; involucre 6–9 mm long (to 15 mm in fruit); inner bracts longer, spreading or reflexed in fruit, green with a reddish apex. Florets slightly exceeding involucre, pale yellow; ligule 2.5–4 mm long. Cypselas obovate, 6–8 mm long (including 3–4 mm beak), minutely bristly above, grey-brown; pappus c. 5 mm long. Flowers Sep.–May.