(From above, and image, or spiectre; because it is supposed to drive away evil spirits). St. John's wort perforata, fuga daemonum, androsaemum, Hypericum vulgare; hypericum perforatum Lin. Sp. Pl. 1105. Perforated or common St. John's wort.
This plant has slender, round, reddish, woody stalks; small, obtuse, oblong leaves, set in pairs, which, when held to the light, seem to be perforated; numerous gold coloured pentapetalous flowers on the tops of the branches, followed by blackish husks, full of small seeds. It is perennial, grows wild in the hedges and uncultivated places, and flowers in June and July.
The flowers abound with resin, but with the aid of its abundant mucilage, water dissolves all its active parts. The leaves also contain much resin. Distilled with water, an essential oil is obtained, resembling that of turpentine. To the taste the leaves and flowers are bitterish and subastringent; but though not much used at present, it was in great repute with the ancients j internally in hysteria, hypochondriasis, mania, ulcers haemoptysis, bloody urine, gravel, dysentery, agues, worms, wounds, and bruises; and, outwardly, as an anodyne and a discutient. In the London Pharmacopoeia the flowers are preferred, as containing the greatest proportion of the resinous matter, in which the medical efficacy of the plant is supposed to reside. The dark puncta of the petals, which are vesicles or glands, afford the essential oil of this plant, and give a red colour to rectified spirit and to expressed oils; the latter of which has been long known by the name of oleum hyperici. See Lewis's Materia Medica; Neumann's Chemical Works.
It is the name also for the spiraea and coris.