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SOLANACEAE , in See also:botany, an See also:order of See also:Dicotyledons belonging to the sub-class Sympetalae (or Gamopetalae) and to the See also:series Tubiflorae, containing 75 genera with about 1500 See also:species, widely distributed through the tropics, but passing into the temperate zones. The See also:chief centre of the order lies in Central and See also:South See also:America; 32 of the genera are endemic in this region. It is represented in See also:Britain by three genera including 4 species: Hyoscyamus See also:niger'(See also:henbane), Solanum Dulcamara (Bittersweet) and S. nigrum and Airopa See also:Belladonna (Deadly See also:Nightshade). The See also:plants are herbs, shrubs or small trees. Solanum nigrum, a See also:common See also:weed in See also:waste places, is a See also:low-growing See also:annual See also:herb; S. Dulcamara is an. irregularly climbing herb perennial by means of a widely creeping rhizome; ,4tropa Belladonna is a large perennial herb. The genus Solanum, to which belong more than See also: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, See also:flower-bearing parts of the See also:stem are See also:Ili in A. Datura See also:Stramonium, B. Atropa Belladonna. I, II, III, See also:Flowers on inflorescences of successive orders; b, bract of I; a, f-i, bracts of l l ; a', ¢', 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 li appear to arise from See also:axis II, though in reality originating on axis I. In B the branching is, cincinnal, one of the two branches at each See also:node is undeveloped and its. bract a, a', a'' is smaller than the other member of the pair, 0, (3', which is adnate to and apparently carried up on its axillary See also:branch. raised upon its axillary shoot as far as the next higher node., from which it appears to See also:spring. In Atropa Belladonna (fig. I 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 See also: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 See also:regular, flowers have the parts in See also:fives, 5 sepals, 5 petals, 5 stamens in alternating whorls, and two carpels, which are generally placed obliquely (see fig. 2, floral See also:diagram). The sepals persist and often become enlarged in the See also:fruit. The 0 Solanum—the arrow indicates Schizanthus-the arrow indicates the oblique symmetry of the the oblique symmetry. Two flower: stamens only are functional. corolla is regular and rotate as in Solanum (fig. 2), or See also:bell-shaped as in Atropa, or somewhat irregular as in Hyoscyamus; in the tribe Salpiglossideae, which forms ' a See also:link with the closely allied order See also:Scrophulariaceae, it is zygomorphic, forming, e.g. as in Schizanthus (fig. 3), a two-lipped flower. The stamens are inserted on the corolla See also:tube and alternate with its lobes; in zygomorphic flowers only 'two or four fertile stamens are See also:present; the bilocular anthers open by slits or pores (fig. 4). The flowers are generally conspicuous and adapted to See also:insect See also:pollination; See also:honey is secreted on the disk at the See also:base of the ovary or at the bottom of the corolla tube between the stamens. The ovary is usually bilocular, but in See also:Capsicum becomes unI-locular 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 See also:axile placentas, sometimes few as in Cestrum, a large See also:American genus with tubular flowers, species of which are grown in Britain as See also:green-See also:house plants; the See also:simple See also:style bears a bilobed or sometimes capitate stigma (fig. 5). The fruit is a many-seeded See also:berry, as in 'Solanum, or See also:capsule, as in Datura, where it splits lengthwise, and Hyoscyamus (fig. 6), where it opens by a transverse lid forming a pyxidium. The embryo is See also:bent or straight and embedded in endosperm. The persistent calyx may serve to protect the fruit or aid in its See also:distribution, as in the bladdery structure enveloping the fruit of Physalis or the prickly calyx of species of Solanum. The order is divided into 5' tribes; the See also:division is based on the greater or less curvature of the embryo, the number of ovary cells and the regular or zygomorphic See also:character of the flower. The See also:great See also:majority of the genera belong to the tribe Solaneae, which is characterized by a 2-celled ovary. Lycium is a genus of trees or shrubs, often thorny, with a cylindrical or narrowly bell-shaped corolla and a juicy berry; L. europaeum is a straggling climber often cultivated under the name of See also:tea-plant. For Atropa see NIGHTSHADE: A. Belladonna yields the See also:drug atropin. For Hyoscyamus see See also:HEN-BANE. Physalis, with 45 species mostly in the warmer parts of See also:North and South America, includes P. alkekengi, " See also:winter See also:cherry," and P. peruviana, " Cape See also:gooseberry." Capsicum (q.v.) is widely cultivated for its fruit. which are the so-called chillies. Solanum contains 900 species, among which are S. tuberosum. (See also:potato; q.v.), S. Lycopersicum (See also:tomato; q.v.), and the two See also:British species already mentioned. For Mandragora see See also:MANDRAKE. To the tribe Datureae, characterized by a 4-celled ovary, belongs Datura; D. Stramonium (See also:thorn See also:apple), sometimes found as an See also:escape in Britain, is See also:officinal. Nicotiana, to which belong the See also:tobacco plant (N. tabacum) and other cultivated species, and See also: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, which is characterized by the zygomorphy of the flowers; Salpiglossis and Schizanthus are known in cultivation. Additional information and CommentsThere are no comments yet for this article.
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