There are seven classes of lettuce, distinguished by their morphologies and end uses: 1) Loose leaf, with a dense rosette of leaves arranged in a loose configuration, 2) Crisphead, with leaves that form in a tight, overlapping fashion, 3) Butterhead, with less compact and smaller leaves than the crisphead varieties, 4) Romaine or Cos, with upright, oblong clusters of coarse, thick leaves with large midribs that overlap into loose head- like structures, 5) Celtuce, stem lettuce or asparagus lettuce, grown for their thick, erect stem which is used as both a raw or cooked vegetable, 6) Latin, with elongated leaves and.
