Compositae Lactuca sativa L.
Source: Magness et al. 1971
Lettuce is the most important of the leafy vegetable crops grown in the U.S., both commercially and in home gardens. The plant is an annual, grown from seed, and reaches a usable stage in from 45 to 90 days, depending on kind and climate. Three main types are grown: Heading varieties, Cutting or leaf varieties, and Cos or Romaine. A fourth, very minor type, is the so-called celery lettuce. These are discussed individually, as they differ substantially in exposure of the edible parts during development.
Production in the U.S.: Commercial 205,000 tons, grown on about 220,000 acres. Also very widely planted in home gardens.
Use: Mainly as raw salads.
Part of plant consumed: Leaves.