 | | Description: | Lettuce is a temperate annual or biennial plant most often grown as a leaf vegetable. In Western countries, it is typically eaten cold and raw, in salads, hamburgers, tacos, and several other dishes. In some places, including China, lettuce is typically eaten cooked and use of the stem is as important as use of the leaf.
A lettuce plant has a short stem initially (a rosette growth habit), but when it blooms, the stem lengthens and branches, and it produces many flower heads that look like those of dandelions, but smaller. This is called bolting. When grown to eat, lettuce is harvested before it bolts.
There are six commonly recognised Cultivar Groups of lettuce which are ordered here by head formation and leaf structure; there are hundreds of cultivars of lettuce selected for leaf shape and colour, as well as extended field and shelf life, within each of these Cultivar Groups:
* Butterhead, also called Boston or Bibb forms loose heads; it has a buttery texture. Butterhead cultivars are most popular in Europe. * Chinese lettuce types generally have long, sword-shaped, non-head-forming leaves, with a bitter and robust flavour unlike Western types, appropriate for use in stir-fried dishes and stews. Chinese lettuce cultivars are divided into "stem-use" types (called celtuce in English), and "leaf-use" types such as youmaicai * Crisphead, also called Iceberg, which form tight, dense heads that resemble cabbage. They are generally the mildest of the lettuces, valued more for their crunchy texture than for flavour. Cultivars of iceberg lettuce are the most familiar lettuces in the USA. The name Iceberg comes from the way the lettuce was transported in the US starting in the 1920s on train-wagons covered in crushed ice, making them look like icebergs. * Looseleaf, with tender, delicate, and mildly flavoured leaves. * Romaine, also called Cos, is a head-forming type with elongated leaves. * Summer Crisp, also called Batavian, which form moderately dense heads with a crunchy texture; this type is intermediate between iceberg and looseleaf types.
Some lettuces (especially iceberg) have been specifically bred to remove the bitterness from their leaves. These lettuces have a high water content with very little nutrient value. The more bitter lettuces and the ones with pigmented leaves contain antioxidants. |
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