Lettuce originated from the Mediterranean coast and was introduced to China in the 5th century. The above-ground stems are edible, the skin is white and green, the meat is crisp and tender, the young stems are green, and they turn white and green after maturity. Young stems can be eaten raw, cold, fried, dried or pickled, and young leaves can also be eaten. The stems and leaves contain lettuce, including lettuce (C 1 1H 14O4 or C22H36O7). It tastes bitter and has analgesic effect.
Extended data
Introduction of lettuce varieties
1, pointed leaf lettuce
The plant is tall, with a height of 1.2- 1.8 feet. The leaves are light green, full of shapes, with shallow wrinkles on the page, a little white powder on the back of the leaves, and more white powder. Bamboo shoots are rod-shaped, the upper part is conical, and the length is about 1.5 feet. Distributed in China, Central China or North China. It can be eaten raw or pickled. Strong cold tolerance, heat resistance in seedling stage, and the yield per mu in spring and autumn can reach about 8000 kg.
2. Green lettuce
Newly bred, precocious, heat-resistant, oblong leaves, not easy to glume, generally resistant to bolting. Leaves are 23-30 cm long, obovate, green in color, fleshy stems with thin skin, light green and white skin, and delicious.
Baidu encyclopedia-lettuce
Baidu encyclopedia-lettuce with pointed leaves
Baidu encyclopedia-green lettuce