The receptacle is usually inhabited by a fly, Trypeta arnicivora Löw[1444]; the Pharmacopœia Germania (1872) therefore ordered the florets to be deprived of the involucre and receptacle—“flosculi a peranthodio liberati.” From a chemical point of view the usefulness of this direction may be doubted.
Arnica flowers have a weak, not unpleasant odour; they were formerly used in making the tincture, but as the British Pharmacopœia now directs that preparation to be made with the root, they have almost gone out of use in Great Britain.
Chemical Composition—The flowers appear to be rather richer in arnicin than the root, and are said to be equal if not superior to it in medicinal powers; yet the essential oil they contain is not the same. It is obtained in but extremely small amount and has a greenish or blue coloration. Hesse (1864) has proved that the flowers are devoid of a peculiar volatile alkaloid which had been supposed to be present in them.
RADIX TARAXACI.
Dandelion Root, Taraxacum Root; F. Pissenlit; G. Löwenzahnwurzel.
Botanical Origin—Taraxacum officinale Wiggers T. Dens-leonis Desf., Leontodon Taraxacum L., a plant of the northern hemisphere, found over the whole of Europe, Central and Northern Asia, and North America, extending to the Arctic regions. It varies under a considerable number of forms, several of which have been regarded as distinct species. In many districts it is a troublesome weed.
History—Though the common Dandelion is a plant which must have been well known to the ancients, no indubitable reference to it can be traced in the classical authors of Greece and Italy; it is thought that ἀθάκη of Theophrast and others means it. The word Taraxacum is however usually regarded as of Greek origin;[1445] we have first met with as Tarakhshagun in the works of the Arabian physicians, who speak of it as a sort of Wild Endive. It is thus mentioned by Rhazes in the 10th, and by Avicenna in the 11th century.
The name Dens Leonis, an equivalent of which is found in nearly all the languages of Europe, is stated in the herbal of Johann von Cube[1446] to have been bestowed on this plant by one Wilhelm, a surgeon, who held it in great esteem; but of this personage and of the period during which he lived we have sought information in vain, and we may remember that Dens Leonis (“Dant y Llew”) is already met with in the Welsh medicine of the 13th century.[1447]
Dandelion was also much valued as medicine in the time of Gerarde and Parkinson, and is still extensively employed.
Collection—In England, taraxacum root is considered to be in perfection for extract in the month of November, the juice at that period affording an ampler and better product than at any other. Bentley contends that it is more bitter in March, and most of all in July, and that at the former period at least it should be preferred.