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''Hypericum'' 〔''Sunset Western Garden Book,'' 1995:606–607〕 is a genus of 490〔http://hypericum.myspecies.info/ Hypericum Online〕 species of flowering plants in the family Hypericaceae (formerly often considered a subfamily of Clusiaceae). Hypericum is unusual for a genus of its size because a worldwide taxonomic monograph〔 was produced for it by N.Robson (working at the Natural History Museum, London, UK, between 1977 and 2012). Robson recognizes 36 sections within Hypericum. The genus has a nearly worldwide distribution, missing only from tropical lowlands, deserts and polar regions. All members of the genus may be referred to as St. John's wort, though they are also commonly just called hypericum, and some are known as tutsan. The marsh St. John's-worts are nowadays separated into the genus ''Triadenum''.〔(Missouri Botanical Garden ) Retrieved November 23, 2015〕 Hypericums vary from herbaceous annual or perennials 5–10 cm tall to shrubs and small trees up to 12 m tall. The leaves are opposite, simple oval, 1–8 cm long, either deciduous or evergreen. The flowers vary from pale to dark yellow, and from 0.5–6 cm in diameter, with five (rarely four) petals, most having prominent stamens. The fruit is usually a dry capsule which splits to release the numerous small seeds; in some species it is fleshy and berry-like.〔(Fine Gardening ) Retrieved November 23, 2015〕 ==Uses of ''Hypericum''== Some species are used as ornamental plants and have large, showy flowers. Numerous hybrids and cultivars have been developed for use in horticulture, such as ''H.'' × ''moserianum''〔(【引用サイトリンク】url=http://apps.rhs.org.uk/plantselector/plant?plantid=1007 )〕 (''H. calycinum'' × ''H. patulum''), ''H.'' 'Hidcote'〔(【引用サイトリンク】url=http://apps.rhs.org.uk/plantselector/plant?plantid=1001 )〕 and ''H.'' 'Rowallane'.〔(【引用サイトリンク】url=http://apps.rhs.org.uk/plantselector/plant?plantid=1005 )〕 All of the above cultivars have gained the Royal Horticultural Society's Award of Garden Merit. St. John's-worts can occur as nuisance weeds in farmland and gardens. On pastures, some can be more than a nuisance, causing debilitating photosensitivity and sometimes abortion in livestock. The beetles ''Chrysolina quadrigemina'', ''Chrysolina hyperici'' and the St. John's-wort Root Borer (''Agrilus hyperici'') like to feed on Common St. John's-wort (''H. perforatum'') and have been used for biocontrol where the plant has become an invasive weed. ''Hypericum'' species are the only known food plants of the caterpillar of the Treble-bar, a species of moth. Other Lepidoptera species whose larvae sometimes feed on ''Hypericum'' include Common Emerald, The Engrailed (recorded on Imperforate St. John's-wort, ''H. maculatum''), Grey Pug and Setaceous Hebrew Character. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Hypericum」の詳細全文を読む スポンサード リンク
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