LETTUCE, Lactuca, a genus of plants belonging to the natural order composites, sub order cichoracec, having sinalkilowt2rs,withjimbricated bractese, and all the corollas • late, flatly compressed fruit, with r thread-like beak, and thread-lik, soft, deciduous pappos.—The GARDEN LETTUCE (..L. satire) 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 fiat-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, he regarded as sub-varieties of the Coss LETTUCE and the CAB BAGE LETTUCE, the former having the leaves more oblong and upright, requiring to be tied together for the latter with rounder leaves, which spread out nearer the ground, and afterwards boll or roll together into a bead like a small cabbage. The lettuce is easy of digestion, gently laxative, and 'moderately nutritious, and is generally eaten raw with vinegar and 'oil, more rarely as a boiled vegetable. The white and some
what narcotic milky juice of the plant is inspissated, and used under the name of lee tucarium (q.v.), or thridece, as an anodyne, sedative, The best and most useful kind of this juice is obtained by making incisions iu the flowering stems, and allowing the juice which flows to dry upon them. Lettuces are sown in gardeus from time to time, that they may be obtained in good condition during the whole sum mer. In mild winters they may he 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. rirosa) is distinguished by the prickly keel of the leaves, and by a black, smooth seed, with a rather broad margin. It is found in seine parts of Britain. Laclucarium is prepared from its fresh gatheredleaves 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, etc., but is not a native of Britain, which, however, possesses one or two other species in qualities resembling L. virosa.