1911 Encyclopædia Britannica/Nightshade

NIGHTSHADE, a general term for the genus of plants known to botanists as Solanum. The species to which the name of nightshade is commonly given in England is Solanum Dulcamara which is also called bittersweet or woody nightshade (see fig. 1). It is a common plant in damp hedgebanks and thickets, scrambling over underwood and hedges. It has slender slightly woody stems, with alternate lanceolate leaves more or less heart-shaped and auriculate at the base. The flowers are arranged in drooping clusters and resemble those of the potato in shape, although much smaller. The flower clusters spring from the stems at the side of, or opposite to, the insertion of a leaf. The corolla is rotate, of a lilac-blue colour with a green spot at the base of each segment, or sometimes white, and bears the yellow sessile anthers united at their margins so as to form a cone in the centre of the flower. The flowers are succeeded by ovate scarlet berries, ½ in. long, which in large doses appear to be poisonous or, to say the least, dangerous to children, cases of poisoning by them having occurred. Solanum Dulcamara subject to the same parasitic fungus (Phytophthora infestans) as the potato, and may serve as a medium for communicating the spores to the potato if not removed from the hedges of the fields where potatoes are grown. The plant derives its names of “bittersweet” and Dulcamara from the fact that its taste is at first bitter and then sweet. It is a native of Europe, North Africa and temperate Asia, and has been introduced into North America. The dried young branches are known in pharmacy under the name dulcamara.

Fig. 1.—Bittersweet (Solanum Dulcamara), 2/3 nat. size. 1, Flower; 2, fruits, 1/2 nat. size; 3, berry, cut across, enlarged; 4, seed, much enlarged.

Fig. 2.—Deadly Nightshade (Atropa belladonna). Flowering branch, 1/3 nat. size. 1, Flower, after removal of the corolla, 2/3 nat. size; 2, corolla, with stamens, cut open and flattened, 3/5 nat. size; 3, cross section of ovary, much enlarged.

Dulcamara contains a bitter principle yielding by decomposition a sugar dextrose and the alkaloid solanine. It also contains another glucoside dulcamarin, which when boiled with dilute acid splits up into sugar and dulcamaretin. Solanine appears to exert a depressant action on the vagus nerve and an excitant action on the medulla oblongata.

Solanum nigrum differs from S. Dulcamara in having white flowers in small umbels and globose black berries. It is a common weed in gardens and waste places, growing about 12 or 18 in. high, and has ovate, entire or sinuate or toothed leaves. Two varieties of the plant, one with red and the other with yellow berries, are sometimes met with, but are comparatively rare. The berries have been known to produce poisonous effects when eaten by children, and owe their properties to the presence of solanine. In Réunion and Mauritius the leaves are eaten like spinach.

Deadly nightshade, dwale or belladonna (Atropa belladonna) is a tall bushy herb of the same natural order (fig. 2). It grows to a height of 4 or 5 ft., having leaves of a dull green colour, with a black shining berry fruit about the size of a cherry, and a large tapering root. The plant is a native of central and south Europe, extending into Asia, and is found locally in England, chiefly on chalk and limestone, from Westmorland and southwards. The entire plant is highly poisonous, and accidents not infrequently occur through children and unwary persons eating the attractive-looking fruit. Its leaves and roots are largely used in medicine, on which account the plant is cultivated, chiefly in south Germany, Switzerland and France (see Belladonna).

The name nightshade is applied to plants of different genera in other countries. American nightshade is Phytolacca decandra (pokeweed, q.v.). The three-leaved nightshade is an American species of Trillium. The Malabar nightshade is Basella, which is widely used as a pot-herb in India. Enchanter’s nightshade is Circaea lutetiana, a small, glandular, softly-hairy plant, common in damp woods, with slender, erect or ascending stems, paired ovate leaves with long stalks, and small white flowers in terminal racemes, succeeded by a small fruit covered with hooked bristles; it is a member of the natural order Onagraceae, and is not known to possess any poisonous property; the name seems to have been given to it in the first place in, mistake for a species of Mandragora (see Mandrake).