1911 Encyclopædia Britannica/Dandelion

DANDELION (Taraxacum officinale), a perennial herb belonging to the natural order Compositae. The plant has a wide range, being found in Europe, Central Asia, North America, and the Arctic regions, and also in the south temperate zone. The leaves form a spreading rosette on the very short stem; they are smooth, of a bright shining green, sessile, and tapering downwards. The name dandelion is derived from the French dent-de-lion, an appellation given on account of the tooth-like lobes of the leaves. The long tap-root has a simple or many-headed rhizome; it is black externally, and is very difficult of extirpation. The flower-stalks are smooth, brittle, leafless, hollow, and very numerous. The flowers bloom from April till August, and remain open from five or six in the morning to eight or nine at night. The flower-heads are of a golden yellow, and reach 11/2 to 2 in. in width; the florets are all strap-shaped. The fruits are olive or dull yellow in colour, and are each surmounted by a long beak, on which rests a pappus of delicate white hairs, which occasions the ready dispersal of the fruit by the wind; each fruit contains one seed. The globes formed by the plumed fruits are nearly two inches in diameter. The involucre consists of an outer spreading (or reflexed) and an inner and erect row of bracts. In all parts of the plant a milky juice is contained, which has a somewhat complex composition. The chief constituent is taraxacin, a neutral principle. In addition the juice contains taraxacerin (derived from the former), asparagin, inulin, resins and salts. An extract (dose 5-15 grains), a liquid extract (dose 1/2-1 drachm) and a succus (dose 1-2 drachms) of the root are all used medicinally. For the purposes formerly recognized taraxacum is now never used, but it has been shown to possess definite cholagogue properties, and may therefore be prescribed along with ammonium chloride in cases of hepatic constipation, which it very constantly relieves. The root—which is the medicinal product—is most bitter from March to July, but the milky juice it contains is less abundant in the summer than in the autumn. For this reason, the extract and succus are usually prepared during the months of September and October. After a frost a change takes place in the root, which loses its bitterness to a large extent. In the dried state the root will not keep well, being quickly attacked by insects. Externally it is brown and wrinkled, internally white, with a yellow centre and concentric paler rings. It is two inches to a foot long, and about a quarter to half an inch in diameter. The leaves are bitter, but are sometimes eaten as a salad; they serve as food for silkworms when mulberry leaves are not to be had. The root is roasted as a substitute for coffee. Several varieties of the dandelion are recognized by botanists; they differ in the degree and mode of cutting of the leaf-margin and the erect or spreading character of the outer series of bracts. The variety palustre, which affects boggy situations, and flowers in late summer and autumn, has nearly entire leaves, and the outer bracts of its involucre are erect.

Dandelion (Taraxacum officinale).

1, Unopened head; 2, ripe head from which all the fruits except
two have been removed; 3, one floret, enlarged; 4, one fruit.