(From impero, to command, because its leaves extend, and overwhelm the lesser plants which grow near it). Masterwort. Astrantia, magistrantia, ostritium, imperatoria major, astritium, struthium, smyrniom; imperatoria ostruthium Lin. Sp. Pl. 371.
It is an umbelliferous plant, with large winged leaves, divided into three indented segments, producing thick, oblong, striated seeds, surrounded with a narrow leafy margin: the roots are oblong, thick, knobby, jointed with several lateral fibres, brown on the outside, and whitish within; perennial, a native of the Alps and Pyrenees; found in several places on the banks of the Clyde, in Scotland, by Mr. Lightfoot.
The root is warm, grateful, and aromatic, nearly of the nature of angelica; yielding to water, or spirit of wine, its smell, warmth, pungency, and bitterness- On inspissating the spirituous tincture, very little of its flavour exhales; but nearly the whole is carried off in distillation with water. If the root is held in the mouth it provokes saliva; if swallowed, purges; and is sometimes called the countryman's purge: an infusion of it in water, sweetened with honey, is said to be an expectorant. The roots should be taken up in the middle of the winter of the second year. It was considered as an alcxipharmic and sudorific; and in some diseases employed with so much success as to be called divinum remedium; but, at present, it ranks only among the inferior aromatics. A name also for angelica.
Imperatoria nigra. Black masterwort, astran-tin nigra, sanicula faemina; astrantia major Lin. Sp. Pl. 339, is kept in the gardens of the curious, and flowers in July. Its black and fibrous roots only are used.