Lettuce

Lettuce (Lactuca sativa) is an annual plant of the aster or sunflower family Asteraceae. It is most often grown as a leaf vegetable, but also sometimes for its stem and seeds.

There are several types of lettuce, each including many varieties:

Leaf

Also known as looseleaf, cutting or bunching lettuce, this type has loosely bunched leaves and is the most widely planted. It is used mainly for salads.


Crisphead

Better known as the "iceberg" lettuce, the most popular lettuce in the US. It's low in flavor and nutritional content, being composed of even more water than other lettuce types.


Romaine/Cos

Used mainly for salads and sandwiches, this type forms long, upright heads. This is the most often used lettuce in Caesar salads.


Butterhead

Also known as Boston or Bibb lettuce, this type is a head lettuce with a loose arrangement of leaves, known for its sweet flavor and tender texture. It's very popular in Europe.


Summercrisp

Also called Batavian or French Crisp, this lettuce is midway between the crisphead and leaf types. These lettuces tend to be larger, bolt-resistant and well-flavored.


Stem

This type is grown for its seedstalk, rather than its leaves, and is used in Asian cooking, primarily Chinese, as well as stewed and creamed dishes.


The butterhead and crisphead types are sometimes known together as "cabbage" lettuce, because their heads are shorter, flatter, and more cabbage-like than romaine lettuces. There's also Oilseed lettuce. This type is grown for its seeds, which are pressed to extract an oil mainly used for cooking. It has few leaves, bolts quickly and produces seeds around 50 percent larger than other types of lettuce.

History

Lettuce was first cultivated by the ancient Egyptians, who turned it from a weed whose seeds were used to make oil into a plant grown for its leaves. It spread to the Greeks and Romans, who gave it the name "lactuca", from which the modern "lettuce" ultimately derives. By 50 AD, multiple types were described, and it appeared often in medieval writings, including several herbals. The 16th through 18th centuries saw the development of many varieties in Europe, and by the mid-18th century cultivars were described that can still be found in gardens. Europe and North America originally dominated the market for lettuce, but by the late 1900s the consumption of lettuce had spread throughout the world.

Description

Lettuce's native range spreads between the Mediterranean and Siberia, although it has been transported to almost all areas of the world. Plants generally have a height and spread of 6 to 12 inches (15 to 30 cm). The leaves are colorful, mainly in the green and red color spectrums, with some variegated varieties. There are also a few varieties with yellow, gold or blue-teal leaves. Lettuces have a wide range of shapes and textures, from the dense heads of the iceberg type to the notched, scalloped, frilly or ruffly leaves of leaf varieties.

Culinary Use

Lettuce is most often used for salads, although it is also seen in other kinds of food, such as soups, sandwiches and wraps. One type is grown for its stems, which are eaten either raw or cooked. Depending on the variety, lettuce is a good source of vitamin A and potassium, with higher concentrations of vitamin A found in darker green lettuces. It also provides some dietary fiber (concentrated in the spine and ribs), carbohydrates, protein and a small amount of fat. With the exception of the iceberg type, lettuce also provides some vitamin C, calcium, iron and copper, with vitamins and minerals largely found in the leaf.

Source: Wikipedia

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