ARNICA. A genus of plants belonging to the natural order Composites (composite family). The flowers are clustered in heads (capitula), and are surrounded by an involucre composed of two rows of small leaflets called bracts. The outer flowers of the head are strap-shaped (ligulate), and contain pistils only, while the inner or central florets are tubular and have both stamens and pistils. The style is hairy, and the fruit is cylindrical, tapering at each end, and bears at its summit a pappus, consisting of rigid hairs in a single row. The most impor-tant species is Arnica montana (mountain tobacco), a perennial plant found in meadows throughout the northern and central regions of the northern hemisphere, but not extending to Britain. It grows on the mountains of Western and Central Europe. A variety of it, with very narrow leaves, is met with in Arctic Asia and America. The heads of flowers are large, orange yellow, and borne on the summit of the stem or branches. The outer ligulate flowers are an inch in length. The achenes (fruits) are brown and hairy. The root, or rather the root-stock, has been used in Pharmacy. It is contorted and of a dark brown colour, an inch or two in length. It gives off numerous simple roots from its under side, and shows on its upper side the remains of rosettes of leaves. It yields an essential oil in small quantity, and a resinous matter called arnicin. Arnica has been used as a stimulant in low fevers, and also in cases of palsy. It is said also to act iu promoting perspiration. It is a popular remedy for chil-blains, and it is said to prevent the blackness of bruises.

The flowers have also been used in the form of tincture. They have an unpleasant odour. The plant is not much used at the present day. (J. H. B.)