Lactuca serriola L.
Synonym: Lactuca scariola
Aster or Composite
General: plant with milky sap, 30-150 cm tall.
biennial or winter annual.
erect, stout, sometimes stiff-hairy below.
Leaves: alternate, mostly 5-30 cm long and 1-10 cm
wide, prickly on the midrib beneath, more finely so on the
margins, pinnately lobed or (in var. integrata) lobeless,
commonly twisted at the base to lie in a vertical plane,
clasping stem with small, arrow-shaped lobes.
Flowerheads: yellow, 10-15 mm wide, with 13 to 27 ray
florets only, numerous in open clusters. Involucre 10-15
mm high in fruit, with overlapping bracts in 3 rows.
Flowering time: July-September.
Fruits: achenes, gray or yellowish, the body 3-4 mm
long and a third as wide, compressed, prominently
several-nerved on each face, with small spines above, at
least marginally, the slender beak equaling to twice as
long as the body. Pappus of white, hair-like bristles.
A weed of fields and disturbed areas in all parts of MT.
Native of Europe, now naturalized in most of the U.S.
Edible and Medicinal plant, see below.
(click on image for full size)
(click on images for full size)
Young, tender leaves of prickly lettuce have been eaten - raw or cooked. They are said to taste mild and
can make an excellent salad, but the whole plant becomes bitter as it gets older, especially when flowering.
If used as a potherb it needs very little cooking. Caution should be used, however, since large quantities
have been known to cause digestive upsets. Young shoots can be cooked and used as an asparagus substitute.
The whole plant is rich in a milky sap. This sap hardens and dries when in contact with the air. The sap
contains lactucarium, which is an agent that has been used in medicine for its properties of being mildly
pain-relieving, antispasmodic, digestive, urination-inducing, hypnotic, narcotic and sedative. Lactucarium
has effects of a mild opium, but without its tendency to cause digestive upsets. It is not addictive either.
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 for treatment
of warts. Concentrations of lactucarium are highest when the plant flowers. Prickly lettuce should be
used with caution, and never without the supervision of a skilled practitioner because of its mild narcotic
properties. Even normal doses can cause drowsiness, excess doses cause restlessness, and overdoses can
cause death through cardiac arrest.
var. integrata or f. integrifolia:
Leaves mostly without lobes. It may represent merely an infusion of genes from the cultivated lettuce, L. sativa.
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