SOLANACEAE, in botany, a family of dicotyledons belong ing to the sub-class Sympetalae (or Gamopetalae) and to the series Polemoniales, containing 72 genera with about 1,75o species, widely distributed through the tropics, but passing into the tem perate zones. The chief centre of the family lies in Central and South America; 36 of the genera are endemic in this region. It is represented in Britain by three genera including four species: Hyoscyamus niger (henbane), Solanum Dulcamara (bittersweet) and S. nigrum and Atropa Belladonna (deadly nightshade).
It is represented in North America by about 40 species, the conspicuous genera being Solanum (nightshade, bittersweet, horse nettle), Physalis (ground cherry), and Datura (jimson weed).
Nicotiana (tobacco) is represented by two species, one extending from Colorado to Nevada and California, and the other a native of Oregon, but cultivated by the Indians eastward to the Missouri river. The plants are herbs, shrubs or small trees. Solanum nigrum, a common weed in waste places, is a low-growing annual herb ; S. Dulcamara is an irregularly climbing herb perennial by means of a widely creeping rhizome; Atropa Belladonna is a large peren nial herb. The genus Solanum, to which belong more than half the species in the family, contains plants of very various habits in cluding besides herbs, shrubs and trees. The leaves are generally alternate, but in the flower-bearing parts of the stem are often in pairs, an arrangement which, like the extra-axillary position of the flowers or cymes, results from a congenital union of axes. In Atropa Belladonna one of the branches at each node is un developed and there is a pair of unequal leaves ; the smaller sub tends the branch which has not developed, the larger has been carried up from the node below.
The hermaphrodite, generally regular, flowers have the parts in fives, five sepals, five petals, five stamens in alternating whorls, and two carpels, which are generally placed obliquely. The corolla is regular and rotate as in Solomon nigrum, or bell-shaped as in Atropa, or somewhat irregular as in Hyoscyamus; in the tribe Salpiglossideae, which forms a link with the closely allied family Scrophulariaceae (q.v.), it is zygomorphic, forming e.g., as in Schtzanthus, a two-lipped flower. The stamens are inserted on the corolla tube and alternate with its lobes; in zygomorphic flowers only two or four fertile stamens are present. The flowers are generally conspicuous and honey is secreted on the disk at the base of the ovary or at the bottom of the corolla tube be tween the stamens. The ovary is usually bilocular, but in Capsi cum becomes unilocular above, while in some cases an in-growth of a secondary septum makes it 4-celled as in Datura, or irregularly 3- to 5-celled as in Nicandra. The anatropous ovules are generally
numerous on swollen axile placentae. The style is simple and bears a bilobed or capitate stigma. The fruit is a many-seeded berry, as in Solanum, or capsule, as in Datura, where it splits lengthwise, and Hyoscyamus, where it opens by a transverse lid forming a pyxidium. The embryo is bent or straight and embedded in endosperm. The persistent calyx may serve to protect the fruit or aid in its distribution, as in the red bladdery structure enveloping the fruit of Physalis.
The family is divided into five tribes after Wettstein; the divi sion is based on the greater or less curvature of the embryo, the number of ovary cells and the regular or zygomorphic character of the flower. The great majority of the genera belong to the tribe Solaneae, which is characterized by a two-celled ovary. Lycium is a genus of trees or shrubs, often thorny, with a juicy berry; L. chinense (L. barbarum) is a straggling climber often cultivated under the name of tea-plant. For Atropa, see NIGHT SHADE; for Hyoscyamus, see HENBANE. Physalis, with 5o species mostly in the warmer parts of North and South America, includes P. alkekengi, "winter cherry," and P. peruviana, "Cape gooseberry. Capsicum (q.v.) is widely cultivated for its fruit, which are the so-called chillies. Lycopersicon esculentum is the tomato (q.v.) and L. pimpinellifolium is the currant-tomato ; both are native to western South America, as is also Cyphomandra betacea, the tree-tomato. For Mandragora, see MANDRAKE. To the tribe Datureae, characterized by a four-celled ovary, belongs Datura; D. Stramonium (thorn apple), sometimes found as an escape in Britain, is officinal. D. Metel, native to India, and D. meteloides, of the south-western United States, are large-flowered annuals, grown in gardens in warm-temperate countries, as are the tree like shrubs, D. sanguinea, native to Peru ; D. suaveolens, native to Brazil, and D. arborea, of the central Andes. Nicotiana, to which belong the tobacco plant (N. tabacum) and other culti vated species, and Petunia, are American genera belonging to the tribe Cestreae, in which the embryo is straight or only slightly bent, as it is also in the tribe Salpiglossideae ; Salpiglossis and Schizanthus are known in cultivation.
Among other plants of the family grown for ornament are the pepino (Solanum muricatum), Jerusalem-cherry (S. Pseudo Capsicum) , scarlet eggplant (S. integrif oliunt) , tomatillo (Physalis ixocarpa) and strawberry-tomato (P. pubescens).
Numerous plants of the family are narcotic-poisonous, especially species of Solanum (nightshade), Atropa (belladonna), Hyoscya mus (henbane) and Datura (stramonium).