Page authors: Don Knoke, David Giblin
Lactuca biennis
tall blue lettuce, wild blue lettuce

Distribution: Yukon Territory to California, east across most of North America to the Atlantic Coast.

Habitat: Moist places at low to middle elevations.

Flowers: June-August

Origin: Native

Growth Duration: Annual

Conservation Status: Not of concern

Pollination: Bees, flies, beetles, wasps


Robust annual or biennial, 6-20 dm. tall, the juice milky, glabrous except for some hairs on the mid-vein on the underside of the leaves.


Leaves pinnatifid or toothed, 10-40 cm long and 4-20 cm. wide, distributed evenly along the stem.


Heads numerous in a rather narrow, elongate inflorescence, 13-34 flowered; involucre 10-14 mm. high, cylindric but broadening at the base, the bracts imbricate; corollas all ligulate, bluish to white, the tube more than half as long as the ligule; pappus of light brown capillary bristles.


Achenes 4-5.5 mm. long, compressed and thin-edged, nearly beakless.

Accepted Name:
Lactuca biennis (Moench) Fernald
Publication: Rhodora. 42: 300. 1940.

Synonyms & Misapplications:
Sonchus biennis Moench
Additional Resources:

PNW Herbaria: Specimen records of Lactuca biennis in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Lactuca biennis checklist entry.

OregonFlora: Lactuca biennis information.

E-Flora BC: Lactuca biennis atlas page.

CalPhotos: Lactuca biennis photos.

USDA Plants: Lactuca biennis information.

28 photographs:
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