Lactuca serriola L.
prickly lettuce
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.
N.: Auckland, Bay of Plenty, Waikato, Hawke's Bay, Wairarapa, Wellington; S.: Nelson, Marlborough, Canterbury, Otago.
Eurasia, N. Africa 1914
Waste land, railway yards, gardens, roadsides, riverbeds, scrub.
Plants with undivided lvs have been referred to in N.Z. as var. integrata Gren. et Godron. These have no other differences, and several other Lactuca spp. are similarly polymorphic for lf division, so the var. is not accepted as distinct. L. serriola is probably the wild ancestor of L. sativa. It may be confused with L. virosa, and characters to distinguish young plants are described under that sp.
