Lettuce

Lettuce (Lactuca), a genus of plants belonging to the natural order Composite, sub-order Cichoraceæ. The Garden Lettuce (L. sativa) is supposed to be a native of the East Indies, but is not known to exist anywhere in a wild state, and from remote antiquity has been cultivated in Europe as an esculent, and particularly as a salad. It has a leafy stem, oblong leaves, a spreading, flat-topped panicle, somewhat resembling a corymb, with yellow flowers, and a fruit without margin. It is now generally cultivated in all parts of the world where the climate admits of it; and there are many varieties, all of which may, however, be regarded as sub-varieties of the Cos Lettuce and the Cabbage Lettuce, the former having the leaves more oblong and upright, requiring to be tied together for blanching—the latter with rounder leaves, which spread out nearer the ground, and afterwards boll or roll together into a head like a small cabbage. The lettuce is easy of digestion, gently laxative, and moderately nutritious. The white and somewhat narcotic milky juice of this plant is inspissated, and used under the name of Lactucarium or Thridace as an anodyne, sedative, opiate medicine. The best and most useful kind of this juice is obtained by making incisions in the flowering stems, and allowing the juice which flows to dry upon them. In mild winters they may be kept ready for planting out in spring. The other species of this genus exhibit nothing of the bland quality of the garden lettuce. The Strong-scented Lettuce (L. virosa) is distinguished by the prickly keel of the leaves, and by a black, smooth seed, with a rather broad margin. It is found in some parts of Britain. Lactucarium is prepared from its fresh-gathered leaves in the flowering season. The leaves have a strong and nauseous, narcotic and opium-like smell. L. perennis adorns with beautiful blue flowers the stony declivities of mountains and clefts of rocks in some parts of Germany, as in the Harz, &c., but is not a native of Britain, which, however, possesses one or two other species in qualities resembling L. virosa.