Lactuca canadensis L.

Leafy-stemmed annual or usually biennial 3–25 dm, glabrous or occasionally coarsely hirsute, often ± glaucous; lvs highly variable, entire or toothed to pinnately lobed or cleft, sagittate or sometimes narrowed to the base, 10–35 × 1.5–12 cm; heads numerous, small, with 13–22 yellow fls; invol 10–15 mm in fr; achenes blackish, very flat, with a median nerve on each face, transversely rugulose, 4.5–6.5 mm overall, the slender beak from a little more than half to about as long as the body; mature pappus 5–7 mm; 2n=34. Fields, waste places, and woods; Que. and P.E.I. to Sask., s. to Fla. and Tex. July–Sept. (L. sagittifolia; L. steelei)

Thickets, woodland borders and clearings. Moist open places. Usually found in sandy soils. Roadsides, swamps, salt marshes, thickets; at from sea level to 2200 metres.

The young leaves can be added to salads. They can be boiled with one change of water then eaten. They are slightly bitter. The plant accumulates lactucarium towards flowering which is mildly narcotic.

Can be grown by seedlings.