Hypericum perforatum

Hypericum perforatum, known as perforate St John's-wort, common Saint John's wort and St John's wort, is a flowering plant in the family Hypericaceae. Although used as a medicinal herb with possible antidepressant activity, high-quality clinical evidence for such effects is absent, and no H. perforatum drug has been approved by the US Food and Drug Administration. The plant is poisonous to livestock. The primary phytochemical constituent of St John's wort is hyperforin. Perforate St John's wort is a herbaceous perennial plant with extensive, creeping rhizomes. Its reddish stems are erect and branched in the upper section, and can grow up to 1 m (3 ft 3 in) high. The stems are woody near their base and may appear jointed from leaf scars. The branches are typically clustered about a depressed base. It has opposite and stalkless leaves that are narrow and oblong in shape and 1–2 cm (0.39–0.79 in) long. Leaves borne on the branches subtend the shortened branchlets. The leaves are yellow-green in color, with scattered translucent dots of glandular tissue. The dots are conspicuous when held up to the light, giving the leaves the 'perforated' appearance to which the plant's Latin name refers. The flowers measure up to 2.5 cm (0.98 in) across, have five petals and sepals, and are colored bright yellow with conspicuous black dots. The flowers appear in broad helicoid cymes at the ends of the upper branches, between late spring and early to mid summer. The cymes are leafy and bear many flowers. The pointed sepals have black glandular dots. The many stamens are united at the base into three bundles. The pollen grains are ellipsoidal. The black and lustrous seeds are rough, netted with coarse grooves. When flower buds (not the flowers themselves) or seed pods are crushed, a reddish/purple liquid is produced. The specific epithet perforatum is Latin, referring to the perforated appearance of the plant's leaves. It is probable that Hypericum perforatum originated as a hybrid between two closely related species with subsequent doubling of chromosomes. One species is certainly a diploid a subspecies of Hypericum maculatum, either subspecies maculatum or immaculatum. Subspecies maculatum is similar in distribution and hybridizes easily with Hypericum perforatum, but subspecies immaculatum is more similar morphologically. The other parent is most likely Hypericum attenuatum as it possesses the features of Hypericum perforatum that Hypericum maculatum lacks. Though Hypericum maculatum is mostly western in its distribution across Eurasia and Hypericum attenuatum is mostly eastern, both species share distribution in Siberia, where hybridization likely took place. However, the subspecies immaculatum now only occurs in south-east Europe. The common name 'St John's wort' may be used to refer to any species of the genus Hypericum. Therefore, Hypericum perforatum is sometimes called 'common St John's wort' or 'perforate St John's wort' to differentiate it. St John's wort is named as such because it commonly flowers, blossoms and is harvested at the time of the summer solstice in late June, around St John's Feast Day on 24 June. The herb would be hung on house and stall doors on St John's Feast day to ward off evil spirits and to safeguard against harm and sickness to man and live-stock. The genus name Hypericum is possibly derived from the Greek words hyper (above) and eikon (picture), in reference to the tradition of hanging plants over religious icons in the home during St John's Day.