Lactuca sativa L. - Asteraceae - lettuce, (Grüner) Salat, Garten-Lattich
Annual or biennial herb, up to 1m tall; leaves green, glabrous, soft to crispy; flowers yellow.
„Lactuca sativa was first known in cultivation in ancient Egypt. It is widely cultivated as a vegetable in China. Leaves of the species contain Vitamins A, B9, C, and K and can be eaten as a salad. Lactuca sativa has many cultivars, which are usually treated as varieties. Lactuca sativa var. angustata Irish ex Bremer is the most commonly cultivated variety in China, where the thick stems are cooked as a vegetable.“
„Human selection caused a decrease in latex content and bitter taste, loss of prickles of stem and leaf, and absence of early bolting in the cultivated types.“
[Origin and domestication of Lactuca sativa L., De Vries, I.M., Genetic Resources and Crop Evolution, Vol.44(2), 1997, 165-174]
Bitterness of lettuce is associated with sesquiterpene lactones and its derivatives like lactucin-15-oxalate, 8-deoxylactucin 15-oxalate and lactucopicrin oxalate. Tannins based on 4-hydroxyphenyl acetyl esters of glucose with 2,3,4-tri-O-(4-hydroxyphenylacetyl)glucopyranose and homologues as core components are also present.
[Metabolite Profiling of Sesquiterpene Lactones from Lactuca Species - Major latex components are novel oxalate and sulfate conjugates of lactucin and its derivatives., Sessa, R.A., Bennett, M.H., Lewis, M.J., Mansfield, J.W., Beale, M.H., Journal of Biological Chemistry, Vol.275(35), 2000, 26877-26884]
Blackwell, E., A curious herbal, vol.1, t.88 (1737) [E. Blackwell]