The Great Lettuce Lactuca virosa differs e.g. in following attributes from the similar Prickly Lettuce Lactuca serriola: It is up to 2 meters high and its base rosette is usually still available at flower time, while the Prickly Lettuce is typically 1.20 meter high and its base rosette usually has withered at flower time. The leaves of the Great Lettuce are rarely pinnate and standing more or less horizontally, while those of the Prickly Lettuce are often very pinnate and standing almost vertically. The seed of the Great Lettuce is wider than that of the Prickly Lettuce, of which the seed carries bristles at the tip towards the pappus, which is barely the case at the Great Lettuce.