Types of Lettuce
Lettuce or Lactuca sativa is part of the Asteraceae family of plants, along with daisies and sunflowers. Originally, lettuce was cultivated by ancient Egyptians, who valued the seeds for the oil they contained. Over time, they developed varieties that provided nutritious and tasty leaves as well.
The Romans also loved their lettuce; the name lactuca comes from the word lac, meaning milk, and refers to the milky sap that flowed from the base of the plant into its leaves.
There are four main types of lettuce grown commercially today: cos/romaine, loose-leaf, crisphead, and butterhead. Of these four types, you can further differentiate by color, with green leaf and red/purple leaf varieties in each of the four main categories.
The most common lettuce variety, as we’ve seen, is iceberg, which was first developed and sold by Burpee Seed Co. in 1894. Other popular kinds of lettuce include romaine, butter, Bibb, Boston, red leaf, and Little Gem.
There are also a number of leafy salad greens, including endive, frisée, and radicchio, that are commonly referred to as lettuces but are actually members of the chicory family of vegetables.
( Excerpt taken from The Food Revolution Network)