Lactuca serriola L.

Annual or biennial. Stem erect, branching above, finely grooved, glabrous or with patent coarse spinous bristles up to 3–4 mm long below, 50–150–(250) cm tall. Lvs glaucous; rosette and lower stem lvs tapering to base, with stiff hairs and spinous bristles especially on veins beneath, 5–30 × 2–12 cm, deeply runcinate-pinnatifid to undivided; margins finely dentate to bristly ciliate, usually sinuate. Upper lvs becoming glabrous, triangular to obovate to linear, sometimes triangularly 3-lobed at apex, with oblong amplexicaul auricles at base. Infl. diffusely paniculate. Capitula numerous, cylindric. Involucre 8–13 mm long; bracts imbricate, suberect to reflexed at fruiting; outermost bracts triangular to ovate, subacute, 1/4-⅓ length of innermost bracts; inner bracts lanceolate to linear, obtuse to acute. Florets c. 11/2× length of involucre; corollas erect to erecto-patent, yellow. Achenes pale brown to grey, sometimes dark-spotted, 5–9-ribbed on each face, obovate, flattened, finely spiny distally on ribs; body 2.5–3 mm long; beak pale, = body. Pappus fine, white.

[From: Webb et al. (1988) Flora of New Zealand. Volume 4.]

Flowering: (Dec.)–Jan.–Mar.–(Jun.); Fruiting: (Dec.)–Jan.–Mar.–(Jun.)