in botany: A genus of the polygamia equialis order, belonging to the syngenesia class of plants; and in the natural method ranking under the 49th order, Compositae. The receptacle is naked; the calyx imbricated, cylindrical, with a membranaceous margin; the pappus is simple, stipated, or stalked. There are several species, most of which are plants of no use, and never cultivated but in botanic gardens for variety. Those commonly cultivated in the kitchen-garden for use, are, 1. The common or garden lettuce. 2. Cabbage lettuce. 3. Silesia lettuce. 4. Dutch brown lettuce. 5. Aleppo lettuce. 6. Imperial lettuce. 7. Green capuchin lettuce. 8. Verfailles or upright white Cos lettuce. 9. Black Cos. 10. Red Cos. 11. Red capuchin lettuce. 12. Roman lettuce. 13. Prince lettuce. 14. Royal lettuce. 15. Egyptian Cos lettuce.

Culture, &c. The first of these sorts is very common in all gardens, and is commonly sown for cutting very young, to mix with other salad herbs in spring; and the second, or cabbage lettuce, is only this mended by culture. It may be sown at all times of the year, but in the hot months requires to be sown in shady borders. The cabbage-lettuce may also be sown at different seasons, to have a continuation of it through the summer. The first crop should be sown in February, in an open situation; the others at three weeks distance; but the later ones under covert, but not under the drippings of trees. The Silesia, imperial, royal, black, white, and upright Cos lettuces, may be first sown in the latter end of February or the beginning of March, on a warm light soil, and in an open situation; when the plants are come up, they must be thinned to 15 inches distance every way, they will then require no farther care than the keeping them clear of weeds; and the black Cos, as it grows large, should have its leaves tied together to whiten the inner part. Succeeding crops of these should be sown in April, May, and June; and toward the latter end of August they may be sown for a winter crop, to be preserved under glass, or in a bed arched over with hoops and covered with mats. The most valuable of all the English lettuces are the white Cos or the Verfailles, the Silesia, and the black Cos. The brown Dutch and the green capuchin are very hardy, and may be sown late under walls, where they will stand the winter, and be valuable when no others are to be had. The red capuchin, Roman, and prince lettuce, are very early kinds, and are sown for variety; as are also the Aleppo ones for the beauty of their spotted leaves.

Properties. The several sorts of garden lettuces are very wholesome, emollient, cooling salad herbs, easy of digestion, and somewhat loofening the belly. Most writers suppose that they have a narcotic quality; and indeed in many cases they contribute to procure rest; this they effect by abating heat, and relaxing the fibres. The seeds are in the number of the four lesser cold seeds.

The virofa, or strong-scented wild lettuce, which is indigenous in Britain, and grows in some places in considerable abundance, differs very essentially in its qualities from the garden lettuce. Although it has not been introduced into any of the modern pharmacopoeias, yet it has of late been highly extolled for some purposes in medicine. It smells strongly of opium, and resembles it in some of its effects; and its narcotic power, like that of the poppy heads, resides in its milky juice. An extract from the expressed juice is recommended in small doses in dropsy. In dropsies of long standing, proceeding from viscid obstructions, it has been given to the extent of half an ounce a day. It is said to agree with the stomach, to quench thirst, to be gently laxative, powerfully diuretic, and somewhat diaphoretic. Plentiful dilution is allowed during its operation. Dr Collin of Vienna asserts, that out of 24 dropical patients, all but one were cured by this medicine.

LACUNÆ, among anatomists, certain excretory canals in the genital parts of women.