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Bible Encyclopedias
Solanaceae
1911 Encyclopedia Britannica
in botany, an order of Dicotyledons belonging to the sub-class Sympetalae (or Gamopetalae) and to the series Tubiflorae, containing 75 genera with about 1 50o species, widely distributed through the tropics, but passing into the temperate zones. The chief centre of the order lies in Central and South America; 32 of the genera are endemic in this region. It is represented in Britain by three genera including 4 species: Hyoscyamus niger (henbane), Solanum Dulcamara (Bittersweet) and S. nigrum and Atropa Belladonna (Deadly Nightshade).
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 perennial herb. The genus Solanum, to which belong more than half the number of species in the order, contains plants of very various habits including 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. Thus in Datura (thorn apple) (fig. I A), where the branching is dichasial, the leaf which originates at any given node becomes III FIG. I. - Diagrams illustrating branch development in Solanaceae, in A. Datura Stramonium, B. Atropa Belladonna. I, II, III, Flowers on inflorescences of successive orders; b, bract of I; a, a, bracts of II; a', t3', bracts of III, and so on. In A the branching is dichasial and the bracts are adnate to their axillary shoots up to the points at which the next branches arise; thus a. and a appear to arise from axis II, though in reality originating on axis I. In B the branching is cincinnal, one of the two branches at each node is undeveloped and its bract a, a', is smaller than the other member of the pair, 0, 13', which is adnate to and apparently carried up on its axillary branch.
raised upon its axillary shoot as far as the next higher node, from which it appears to spring. In Atropa Belladonna (fig. 1 B) one of the branches at each node is undeveloped and there is a pair of unequal leaves; the smaller subtends the branch which has not developed, the larger has been carried up from the node below.
An interesting anatomical feature is the presence in the stem of bicollateral bundles - that is, the vascular bundles have phloem on the inside as well as on the outside of the xylem.
The hermaphrodite, generally regular, flowers have the parts in fives, 5 sepals, 5 petals, 5 stamens in alternating whorls, and two carpels, which are generally placed obliquely (see fi b. 2, floral diagram). The sepals persist and often become enlarged in the fruit. The FIG. 2. - Floral diagram of FIG. 3. - Floral diagram of Solanum - the arrow indicates Schizanthus - the arrow indicates the oblique symmetry of the the oblique symmetry. Two flower. stamens only are functional.