Hypericum olympicum
Introduction '''''Hypericum olympicum''''', commonly known as the '''Mount Olympus St. John's wort''', is a species of flowering plant in the family Hypericaceae found in the Balkans and Turkey and introduced to western Europe. It has been widely cultivated for centuries because of its large, showy flowers, which are far larger than those of most other species in ''Hypericum.''
Taxonomy ''H. olympicum'' was first described in Carolus Linnaeus's ''Species Plantarum'' in 1753.=== Chemotaxonomy ===''H. olympicum'' contains both hypericin and pseudohypericin, a trait shared in the ''Olympia'' group and sections ''Adenosepalum'' and ''Hypericum,'' which would suggest that the species is more closely related to species in those sections than in other more primitive sections.=== Infraspecifics ===There are eight accepted infraspecifics of ''H. olympicum'', three of which are varieties and five of which are forms. These generally have very little variance from the type of the species, but can have some minor unique features.VarietiesAuthorityDifferentiating FeaturesReference''H. olympicum'' var. ''latifolium''Stef.Smaller flowers and leaves''H. olympicum'' var. ''minus''Heldr. ''ex'' Degen''H. olympicum'' var. ''olympicum''FormsAuthorityReference''H. olympicum'' f. ''macrocalyx''(Velen.) N. Robson''H. olympicum'' f. ''minor''Hausskn.''H. olympicum'' f. ''olympicum''''H. olympicum'' f. ''tenuifolium''(D. Jord & Kož.) N. Robson''H. olympicum'' f. ''uniflorum''Boiss. & Balansa
Description The species is a shrub or subshrub that grows to be  tall. It can grow in an erect to decumbent manner, or rarely prostrate. It can have few to numerous stems, and it is caespitose, occasionally rooting, and unbranched below its flowers. The stems' internodes are  long, and can be either short or longer than the leaves.The leaves are spreading to erect, and are more or less glaucous, and are  in size. They are elliptic or rarely lanceolate-elliptic, are concolorous and thinly coriaceous. Their apex is acute to subacute or rounded-obtuse, with a rounded or cuneate base. They have 0-3 pairs of lateral veins and are unbranched (at least visibly). The laminar glands are pale and not prominent, and the intramarginal glands are black, small, and few in number. The plant is usually 1–5 flowered, but can have up to nine flowers that grow from three nodes, and rarely from one lower node. Their pedicels are  long and rather stout. The bracts are reduced-foliar, are broadly imbricate, and lack black glands, and the bracteoles are similar but smaller in size. The flowers are  in diameter, and their buds are ovoid-pyramidal and rounded. The sepals are either unequal or subequal, are broadly imbricate, and are paler than the leaves. They are , and are broadly ovate to lanceolate, and have a rounded base. They are entire, large, pointed, and persistent in fruit. They have 9–15 veins that are branching. Their laminar glands are pale and linear, and there are sometimes a few that are black and punctiform. Their marginal glands are normally absent, but there can rarely be one or two black apical ones. Their petals are golden or pale yellow, and can have a tinge or lines of red. They are , and there are around 2 times as many of them as sepals. They are rounded and their apiculus is short, and they are acute to obtuse. Their laminar glands are pale and linear, and their marginal glands are absent or black, and there are one to around seven of them. There are around 65–125 (0.9 times as many sepals) stamens that are  long. The ovaries are  and are broadly ovoid, the styles are  and there are six to eight times as many as the ovaries.The seed capsule is  and is shorter than the sepals, and is shaped broadly oval-like to spherical. The seeds are a dark brown color, and are around  with shallow testa.=== Similar species ===''Hypericum olympicum'' is very similar in appearance to ''Hypericum polyphyllum'', but there are many key differences to tell them apart. Most reliably, the leaves of ''H. olympicum'' are far less glandular, with at most one irregular line of glands, whereas the leaves of ''H. polyphyllum'' always have a full regular row and many scattered glands. In addition, whereas the sepals of ''H. olympicum'' are almost always undotted, the sepals of ''H. polyphyllum'' are usually dotted all over with black glands. Lastly, since ''H. polyphyllum'' is not cultivated, if the plant is in cultivation or shows cultivated characteristics, it is most likely ''H. olympicum''.
Distribution and habitat The species is native to Southeastern Serbia, Macedonia, Albania, Bulgaria, Greece (excluding Crete and western Aegean islands), and northwestern Turkey. The species was first introduced to England in 1676 by Sir George Wheeler from seeds found in Turkey, and it was cultivated at the Oxford Botanical Garden. The species has also been recorded as establishing itself in Belgium and France, where it is considered an invasive species.It can be found in sandy, stony, and sometimes grassy places or among rocks in open ground,  or in pine woodland at elevations of 0–2000 m.
Cultivation The RHS Award of Garden MeritBecause of its large, showy flowers, relative hardiness, and dense shape, the species is valued among gardeners, specifically in the United Kingdom. It has been noted for these properties and won several awards, including in 1930, under the incorrect name of ''H. fragile'', winning the Royal Horticultural Society's Award of Garden Merit. While the species is not at all harmful to humans, it can be toxic to dogs, cats, and horses, and should be planted away from such animals.It can be grown in chalk, clay, sand, or loam, and requires moist ground, but with sharp drainage. As it requires sharp drainage to prevent winter rot, it is a suitable subject for the rockery or alpine garden. The species requires pH to be between 6.1 and 7.8, which means it can tolerate both mildly acidic and mildly alkaline conditions. The plant usually takes 5–10 years to reach its full height, but much less than that to reach maturity.The species should be planted in May or June, will flower from June to August, and cuttings should be taken from May to July.+HardinessHardiness ZoneLowest Temperature5a5b6a6b7a7b8a8b=== Cultivars ===There are several cultivated forms of ''H. olympicum'', with ''H. olympicum'' 'Citrinum' being by far the best known. So-called because of its lemon-colored petals, it is often the plant that is found in home or botanical gardens.InfraspecificCultivar NameUnique FeaturesReference''Hypericum olympicum'' f. ''uniflorum'''Citrinum'Lemon-colored flowers, larger flower size''Hypericum olympicum'''Sulphureum'Lance shaped leaves''Hypericum olympicum'' f. ''minus'''Variegatum'Leaves variegated when new
Uses === Folk medicine ===''H. olympicum'' f. ''olympicum'' is used alongside other ''Hypericum'' species in parts of rural Turkey as traditional folk medicine. Typically, its flowers are harvested and used to treat stomach aches, cuts, and burns.=== Essential oils ===''H. olympicum'' contains numerous essential oil compounds, with the main components being (''E'')‐anethole (used as an aromatic substance), β‐farnesene (used as a constituent to essential oils), and spathulenol. Other components included germacrene D  and (''E'')‐caryophyllene, as well as an unusually high amount of terpenes.+Essential oil components by relative percentageSampleAlkanesMonoterpene hydrocarbonsOxygenated monoterpenesSesquiterpene hydrocarbonsOxygenated sesquiterpenesOthers''H. olympicum''8.25.94.747.913.27.3''H. perforatum''18.031.63.035.243.6 -''H. tetrapterum''21.9''trace''''trace''43.619.51.0=== Antimicrobial ===While as of 2019 extracts from the species are not currently used as antibacterials, they do contain antibacterial properties. Specifically, the plant contains new types of acylphloroglucinol that have been given the name olympicin after the species' name.=== Antidepressant ===Similarly, as of 2019, ''H. olympicum'' is not widely used as an antidepressant in the way that ''Hypericum perforatum'' is, but it has been shown to have many similar or better antidepressant properties. Specifically, the amentoflavone in ''H. olympicum'' was shown to have previously unstudied antidepressant capabilities.=== Anticancer ===''H. olympicum'' has been studied alongside other ''Hypericum'' species for their ability to suppress the growth of cancer in several ways. The species has been shown to have minor antigrowth effects on certain types of lung cancer, slowing the replication of cancerous cells in a laboratory setting. It has also been shown to help induce apoptosis in damaged cells because of the genotoxic properties of some of its chemical constituents. The species has not had any of its extracts approved for anticancer regimens.=== Antioxidant ===''H. olympicum'' contains a smaller amount of flavonoids and tannins than other ''Hypericum'' species, but still displays significant antioxidizing capabilities, which suggests there are significant amounts of other undetected compounds in the plant.+Antioxidants compared to ''H. perforatum''SampleDPPH%ABTS%'''FRAP μM TE/g dw'''''H. olympicum''58.8 ± 0.157.9 ± 0.189.9 ± 0.2''H. perforatum''77.6 ± 0.581.2 ± 0.432.4 ± 0.5
Gallery File:Hypericum olympicum 2016-09-10 4339.jpg|Young plantFile:Hypericum olympicum L. (AM AK298043-4).jpg|Beginning to flowerFile:National Botanic Garden,Dublin,Ireland - panoramio (27).jpg|In full bloomFile:Hypericum adenophyllum-IMG 4797.jpg|Full bloom detailFile:Hypericum olympicum 2015-07-01 4026.jpg|Flower detailFile:Hypericum olympicum 2016-09-10 4338b.jpg|In fruit
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