Lactuca canadensis
L.
Canada Lettuce
(c) Alex Zorach, some rights reserved (CC BY), uploaded by Alex Zorach
(c) Douglas Goldman, some rights reserved (CC BY-SA), uploaded by Douglas Goldman
(c) David Rankin, some rights reserved (CC BY-NC), uploaded by David Rankin
What to Eat
Edible parts: Leaves
Young leaves and stems - raw or cooked[46, 55, 61, 85, 105, 177]. Cooked and eaten as greens.
Known Hazards
Where to Find It
Eastern N. America - Nova Scotia to British Columbia, south to Georgia and Colorado.
NORTHERN AMERICA: Canada (Yukon, Québec, Nova Scotia, Ontario, Prince Edward Island, New Brunswick, Manitoba (east), British Columbia), United States (Connecticut, Indiana, Maine, Massachusetts, Michigan, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Vermont, West Virginia, Illinois, Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, Oklahoma, South Dakota, Wisconsin, Colorado, Idaho, Montana, Oregon, Washington, Wyoming, Alabama, Arkansas, Delaware, Florida, Georgia, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, South Carolina, Tennessee, Virginia, District of Columbia, New Mexico, Texas (east), Arizona, California, Nevada, Utah)
How to Identify
Lactuca canadensis is a BIENNIAL growing to 3 m (9ft 10in). It is in flower from July to September, and the seeds ripen from August to October. The species is hermaphrodite (has both male and female organs) and is pollinated by Insects. Suitable for: light (sandy) and medium (loamy) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil.
How to Grow
Prefers a light sandy loam. Hybridizes in the wild with L. ludoviciana and the two species can sometimes be difficult to separate.
Propagation: Seed - sow spring in situ and only just cover the seed. Germination is usually fairly quick.
Medicinal Uses
Analgesic Diuretic Hypnotic Nervine Sedative Warts. The whole plant is rich in a milky sap that flows freely from any wounds. This hardens and dries when in contact with the air. The sap contains 'lactucarium', which is used in medicine for its anodyne, antispasmodic, digestive, diuretic, hypnotic, narcotic and sedative properties[9, 21, 46, 165, 192, 207, 213, 222, 238]. Lactucarium has the effects of a feeble opium, but without its tendency to cause digestive upsets, nor is it addictive. It is taken internally in the treatment of insomnia, anxiety, neuroses, hyperactivity in children, dry coughs, whooping cough, rheumatic pain etc. Concentrations of lactucarium are low in young plants and most concentrated when the plant comes into flower. It is collected commercially by cutting the heads of the plants and scraping the juice into china vessels several times a day until the plant is exhausted. An infusion of the fresh or dried flowering plant can also be used. The plant should be used with caution, and never without the supervision of a skilled practitioner. Even normal doses can cause drowsiness whilst excess causes restlessness and overdoses can cause death through cardiac paralysis. Some physicians believe that any effects of this medicine are caused by the mind of the patient rather than by the medicine. The sap has also been applied externally in the treatment of warts.
