Lactuca sativa L.

Glabrous annual or biennial. Stem erect, branching above, grooved, c. 20-60 cm tall. Rosette and lower stem lvs bright green, tapering to base, 4-10-(15) × 3-8-(12) cm, deeply 1-2-pinnatifid; lobes broad, finely toothed, sinuate or crisped. Upper lvs becoming glaucous and pruinose-papillate, sessile, ternatifid or not divided, triangular to ovate, with rounded to oblong subamplexicaul auricles at base. Infl. diffusely paniculate. Capitula numerous, narrowly ovoid. Involucre (6)-10-12 mm long; bracts imbricate, erect or suberect at fruiting; outermost bracts ovate, obtuse, c. 1/4 length of innermost bracts; inner bracts lanceolate, obtuse. Florets 1.5-2× length of involucre; corollas erect to erecto-patent, pale yellow, sometimes violet-streaked. Achenes grey, 5-9-ribbed on each face, obovate, flattened, scabrid distally on ribs; body 3-3.5 mm long; beak pale, = body. Pappus fine, white.

A temperate plant. Plants are grown throughout the country of Papua New Guinea but particularly in the highlands and mainly for sale. It grows best between 700-2,350 m above sea level in PNG. Leafy forms are used in cooking in many parts of Asia. It suits hardiness zones 6-11.

Eaten raw or in soups. The sprouted seeds can be used in salads or sandwiches. Leaves can be dried and stored. The leaves are used for sarma in Turkey. They are rolled around a filling of rice or minced meat.

Plants are grown from seeds and often transplanted. Seedlings are transplanted after 30-35 days and spaced 45 cm apart. Seeds need to be sown very shallowly. In hot places lettuce develops a bitter taste if transplanted or checked in their growth. Cutting the tap root can stop plants seeding quickly.