General: plant with milky sap, 20-100 cm tall. Growth habit: perennial from white, deep-seated, creeping root, often growing in patches. Stems: erect, hairless or almost so.
Leaves: alternate, narrowly lance-shaped, 5-18 cm long and 6-35 mm wide, entire, or the lower ones more or less with triangular, backward-pointing lobes or sharply toothed, often with waxy coating beneath.
Flowerheads: blue, showy, about 2 cm wide, with 18-50 ray florets only, several in open clusters. Involucre 15-20 mm high in fruit, with overlapping bracts in 3 rows.
Fruits: achenes, 4-7 mm long, the slender body moderately compressed, prominently several-nerved on each face, the beak stout, often whitish, equaling or less than half as long as the body. Pappus of white, hair-like bristles.
Mostly in meadows, thickets, and other moist places, plains to foothills, in all parts of MT. Also in AK and CA to MN and MO.
Young leaves - raw or cooked - of blue lettuce have been eaten by Native tribes. However, caution should be used, because of the mild narcotic properties of the plant, see below.
A tea of the roots and stems has been used by the Okanagan-Colville Indians of British Columbia in the treatment of diarrhea in children. Hemorrhoids have been treated by applying a moist, usually warm or hot mass of plant material. The whole plant is rich in a milky sap, containing 'lactucarium', which is used in medicine for its mildly pain-relieving, antispasmodic, digestive, urination-inducing, hypnotic, narcotic and sedative properties. Lactucarium has mild narcotic effects. It has been taken internally in the treatment of insomnia, anxiety, neuroses, hyperactivity in children, dry coughs, whooping cough, rheumatic pain etc. The sap has also been applied externally in the treatment of warts. The plant should be used with caution, and never without the supervision of a skilled practitioner. Even normal doses can cause drowsiness, excess causes restlessness and overdoses can cause death through cardiac paralysis.
Our specimen belong to var. pulchella (Pursh) Breitung.