View source for Biology:Hypericum

{{Short description|Genus of flowering plants known as St. John's worts}}
{{Automatic taxobox
| fossil_range = {{fossilrange|40.4|0|[[Earth:Eocene|Eocene]] - recent|ref=<ref name=mobot>{{Cite web |title=Malpighiales|url=https://mobot.org/MOBOT/research/APweb/orders/malpighialesweb.htm|access-date=2023-06-16 |website=www.mobot.org}}</ref>}}
| image = Saint John's wort flowers.jpg
| image_caption = ''[[Biology:Hypericum perforatum|Hypericum perforatum]]''
| taxon = Hypericum
| authority = [[Biography:Carl Linnaeus|L.]]
| subdivision_ranks = Species
| subdivision = [[Biology:List of Hypericum species|{{circa|lk=n}} 510]]{{r|powo}}
| synonyms = {{collapsible list
|''Adenotrias'' <small>Jaub. & Spach</small>
|''Androsaemum'' <small>Duhamel</small>
|''Androsemum'' <small>[[Biography:Johann Heinrich Friedrich Link|Link]]</small>
|''Ascyrum'' <small>[[Biography:Carl Linnaeus|L.]]</small>
|''Lianthus'' <small>N.Robson</small>
|''Olympia'' <small>Spach</small>
|''Sanidophyllum'' <small>[[Biography:John Kunkel Small|Small]]</small>
|''Santomasia'' <small>N.Robson</small>
|''Sarothra'' <small>[[Biography:Carl Linnaeus|L.]]</small>
|''Takasagoya'' <small>Y.Kimura</small>
|''Triadenia'' <small>Spach</small>
}}
}}

'''''Hypericum''''' {{IPAc-en|ˌ|h|aɪ|ˈ|p|iː|r|ᵻ|k|əm}} is a [[Biology:Genus|genus]] of [[Biology:Flowering plant|flowering plant]]s in the family [[Biology:Hypericaceae|Hypericaceae]] (formerly considered a subfamily of [[Biology:Clusiaceae|Clusiaceae]]).<ref name="cabi">{{cite web |title=''Hypericum perforatum'' (St John's wort) |url=https://www.cabi.org/isc/datasheet/28268 |publisher=CABI |access-date=22 February 2019 |date=27 September 2018}}</ref><ref name="usda">{{cite web |title=''Hypericum perforatum'' L. (St. John's wort) |url=https://plants.usda.gov/core/profile?symbol=HYPE |publisher=Natural Resources Conservation Service, US Department of Agriculture |access-date=22 February 2019 |date=2019}}</ref>  The genus has a nearly worldwide distribution, missing only from tropical lowlands, deserts and polar regions.<ref name="cabi2">{{cite web|url=https://www.cabi.org/isc/datasheet/28268|title=''Hypericum perforatum'' (St John's wort)|date=27 September 2018|publisher=CABI|access-date=22 February 2019}}</ref> Many ''Hypericum'' species are regarded as [[Earth:Invasive species|invasive species]] and [[Biology:Noxious weed|noxious weed]]s.  All members of the genus may be referred to as '''St. John's wort''', and some are known as '''goatweed'''.<ref name="cabi" /> The white or pink flowered marsh St. John's worts of North America and eastern Asia are generally accepted as belonging to the separate genus ''[[Biology:Triadenum|Triadenum]]'' <small>Raf.</small><ref>{{Cite web|title=Triadenum in Flora of North America @ efloras.org|url=http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=133357|access-date=2021-12-15|website=www.efloras.org}}</ref><ref>{{Cite journal|last=Robson|first=N. K.|date=2021|title=Studies in the genus Hypericum L.(Hypericaceae) 9. Addenda, corrigenda, keys, lists and general discussion.|url=https://www.biotaxa.org/Phytotaxa/article/view/phytotaxa.72.1.1|journal=Phytotaxa|volume=72|pages=1–111|doi=10.11646/phytotaxa.72.1.1}}</ref>

''Hypericum'' is unusual for a genus of its size because a worldwide taxonomic [[Monograph|monograph]]<ref name="hypericum online2">[http://hypericum.myspecies.info/ Hypericum Online]</ref> was produced for it by Norman Robson (working at the [[Biology:Natural History Museum, London|Natural History Museum, London]]). Robson recognizes 36 sections within ''Hypericum''.

==Description==
[[File:Hypericum hidcoteense.jpg|left|thumb|Hypericum hidcoteense]]

''Hypericum'' species are quite variable in habit, occurring as trees, shrubs, annuals, and perennials. Trees in the sense of single stemmed woody plants are rare, as most woody species have multiple stems arising from a single base. Shrubs have erect or spreading stems but never root from nodes that touch the ground. However, perennial herbs tend to root from these horizontal nodes, especially those that occur in wet habitats. Annual herbs tend to have [[Biology:Taproot|taproot]]s with a developed system of secondary hair roots. Many species of ''Hypericum'' are completely glabrous, others have simple uniseriate hairs, and some species have long, fine hairs.<ref name=Chemo>{{cite journal |title= Taxonomy and chemotaxonomy of the genus Hypericum |last2= Crocket |first2= Sara L. |last1= Robson |first1= Norman K. B. |journal= Medicinal and Aromatic Plant Science and Biotechnology |volume= 5 |pages= 1–13 |number= Special Issue 1 |year= 2011 |publisher= Europe PMC Funders |pmc= 3364714 |pmid= 22662019 }}</ref>

[[File:Hypericum-perforatum(Blatt).jpg|thumb|Glandular dots on a leaf of ''Hypericum perforatum'']]
Two types of glands form the characteristic punctiform patterns of ''Hypericum'', "dark glands" and "pale glands". Dark glands consist of clusters of cells with a distinct black to reddish color. Their hue is indicative of a presence of naphthodianthrone, either [[Chemistry:Hypericin|hypericin]] or pseudohypericin, or both. These glands occur in about two-thirds of ''Hypericum'' sections and are usually restricted to certain organs. When these glands are crushed, the naphthodianthrones give a red stain. [[Biography:Paracelsus|Paracelsus]] called the red secretions "Johannes-blut" in the 16th century, linking the plant to the martyr St. John and giving rise to the English and German common names of "St. John's wort". The pale glands, forming the pellucid dots, are each a schizogenous intracellular space lined with flattened cells that secrete oils and [[Chemistry:Phloroglucinol|phloroglucinol]] derivates, including [[Chemistry:Hyperforin|hyperforin]]. The distribution of these hypericin glands dissuades generalist herbivores from feeding on the plants. When generalist insects feed on ''[[Biology:Hypericum perforatum|Hypericum perforatum]]'', 30-100% more naphthodianthrones are produced, repelling the insects.<ref name=Chemo/>

[[File:Hypericum subalatum stem.jpg|thumb|The four-lined stem of ''Hypericum subalatum'']]
The four thin ridges of tissue along the stems are closely to the opposite-decussate leaves of ''Hypericum''. The ridges can be minor, just being called "ridges", or prominent, being called "wings". [[Biology:Terete|Terete]], two-lined, and six-lined stems can occur occasionally. When a species has a tree or shrub habit, the internodes become mostly terete with age, though some trace of lines can still be detected in mature plants. The number of lines is an important distinguishing characteristic; for example, ''H. perforatum'' and ''Hypericum maculatum'' are easily confused save for ''H. perforatum'' having two lines and ''H. maculatum'' having four. The pale and dark glands are present on stems of various species, and other various species have stems without any glands. In section ''Hypericum'', the glands are only present on stem lines, and in other sections, including ''Origanifolia'' and ''Hirtella'', the glands are distributed across the stems.<ref name=Chemo/>

Nearly all leaves of ''Hypericum'' species are arranged opposite and decussate, an exception being section ''Coridium'' in which whorls of three to four leaves occur. The leaves lack [[Biology:Stipule|stipule]]s and can be sessile or shortly [[Biology:Petiole (botany)|petiolar]], though long petioles exist in sections ''Adenosepalum'' and ''Hypericum''. Basal articulation can be present, in which case leaves are deciduous above the articulation, or absent, in which case the leaves are persistent. Some species in sections ''Campylosporus'' and ''Brathys'' have an [[Biology:Auricle (botany)|auricle]]-like, reflexed leaf base, whereas true auricles only exist in sections ''Drosocarpium'', ''Thasia'', and ''Crossophyllum''. Laminar venation is highly variable, being dichotomous to pinnate to densely reticulate. Leaves are typically ovoid to elongate to linear in shape. Leaves are typically shorter than the internodes. Pale or dark glands can be present on or near the leaf margin and on the main leaf surface.<ref name=Chemo/>

Typically there are four or five [[Biology:Sepal|sepal]]s, though in section ''Myriandra'' there are rarely three. When five sepals are present they are quincuncial, and when four sepals are present they are opposite and decussate. Sepals can be equal or unequal. Sepals can be united at their base, as seen in sections ''Hirtella'', ''Taeniocarpium'', and ''Arthrophyllum''. The margins are variable, having marginal glands, teeth, or hairs. The presence or absence of dark glands on the sepals is a useful distinguishing characteristic.<ref name=Chemo/>

[[File:Hypericum.flower.750pix.jpg|thumb|Yellow petals of ''Hypericum'' x ''hidcoteense'' 'Hidcote']]
Almost all ''Hypericum'' petals are yellow, though a range of color exists from a pale lemony hue to a deep orangish-yellow. Exceptions include the white or pinkish petals of ''Hypericum albiflorum'' var. ''albiflorum'' and ''H. geminiflorum''. Many species have petals that are lined or tinged with red, including the deep crimson petals of ''H. capitatum'' var. ''capitatum''. Petal lengths can be equal or unequal. The petals are mostly asymmetrical except those of sections ''Adenotrias'' and ''Elodes''. In those two sections, sterile bodies have developed between the [[Biology:Stamen|stamen]] [[Biology:Fascicle (botany)|fascicle]]s, working as lodicules to spread the petals of the pseudotubular flower, a specialized pollination mechanism. Nearly all species have glands on their petals; only section ''Adenotrias'' has completely eglandular petals. It has been hypothesized that the intensity of red on the petals is correlated with the hypericin content of the glands, but other pigments including skyrin derivatives can create a red color.<ref name=Chemo/>

''Hypericum'' flowers have four or five fascicles that have, in total, five to two hundred stamens. The fascicles can be free or fused in various ways, often into three apparent fascicles. In sections ''Myriandra'', ''Brathys'', and some of ''Trigynobrathys'', the stamens form a ring. Though stamens are usually persistent, some are deciduous. The stamens have an anther gland on the connective tissue, varying in color from amber to black.<ref name=Chemo/>

The [[Biology:Ovary (botany)|ovaries]] are three or five-merous, occasionally two-merous, with a corresponding number of free or united [[Biology:Style (botany)|style]]s. Developing seeds are borne on axile or parietal placentae, with at least two ovules per placenta. ''Hypericum'' fruits are dissimilar to most of [[Biology:Hypericaceae|Hypericaceae]], being capsular and dehisce from the apex. The capsule can be dry or remain fleshy when mature. The capsules have elongate or punctate glands on their surface that create various shapes and patterns. These glands are typically pale amber, though in section ''Drosocarpium'' the glands are reddish-black. Extractions of these glands in certain species yielded [[Chemistry:Phloroglucinol|phloroglucinol]] and [[Biology:Terpenoid|terpenoid]] derivatives, suggesting a connection between these glands and the pale glands of vegetative tissue. Seeds of ''Hypericum'' species are small and range in color from a yellowish brown to dark purplish brown. The seeds are cylindric to ellipsoid and may have narrow wings. In some seeds, a basal ridge may be present, and rarely in section ''Adenotrias'' an apical caruncle is present which attracts ants to disperse seeds. Some species have highly specific germination and survival condition requirements. For example, ''[[Biology:Hypericum lloydii|H. lloydii]]'' is susceptible to a fungal infection as a seedling if conditions are too moist, whereas other species including ''H. chapmanii'' can grow underwater.<ref name=Chemo/>

==Taxonomy==
{{Main|Biology:List of Hypericum species|Biology:List of Hypericum nothospecies}}
There are over 490 species in the genus.<ref name="hypericum online2"/> The name ''hypericum'' derives from {{lang|grc|ὑπέρεικος}} ''hypereikos'' (variants: {{lang|grc|ὑπέρεικον}} ''hypereikon'' and {{lang|grc|ὑπερικόν}} ''hyperikon''),<ref name="LSJ">{{LSJ|u(pe/reikos|ὑπέρεικος|ref}}.</ref> i.e. the Greek name for Hypericum crispum and Hypericum revolutum, itself possibly meaning "above pictures",<ref name=gledhill2008>{{cite book |first=David |last=Gledhill |title=The Names of Plants, 4th edition |url=https://archive.org/details/namesplants00gled_746 |url-access=limited |publisher=Cambridge University Press|year=2008 |isbn=978-0-521-86645-3 |page=[https://archive.org/details/namesplants00gled_746/page/n217 208]}}</ref> for its use over shrines to repel evil spirits, though some have translated it as "above the heath".<ref name=gledhill2008 /><ref name=focr17>{{cite book |last1=Wilhelm |first1=Gerould |last2=Rericha |first2=Laura |author-link2=Laura Rericha |date=2017 |title=Flora of the Chicago Region: A Floristic and Ecological Synthesis |publisher=Indiana Academy of Sciences}}</ref>

===Sections===
''Hypericum'' is broken up into 36 sections, each with its own subsections and species. They include:
{{Div col|gap=2em|colwidth=10em}}
*''Adenosepalum''
*''[[Biology:Hypericum sect. Adenotrias|Adenotrias]]''
*''[[Biology:Hypericum sect. Androsaemum|Androsaemum]]''
*''[[Biology:Hypericum sect. Arthrophyllum|Arthrophyllum]]''
*''Ascyreia''
*''Brathys''
*''[[Biology:Hypericum sect. Bupleuroides|Bupleuroides]]''
*''[[Biology:Hypericum sect. Campylopus|Campylopus]]''
*''[[Biology:Hypericum sect. Concinna|Concinna]]''
*''Coridium''
*''Crossophyllum''
*''Drosocarpium''
*''Elodeoida''
*''Graveolentia''
*''[[Biology:Hypericum sect. Heterophylla|Heterophylla]]''
*''Hirtella''
*''Humifusoideum''
*''Hypericum''
*''[[Biology:Hypericum sect. Inodora|Inodora]]''
*''Monanthama''
*''[[Biology:Hypericum sect. Myriandra|Myriandra]]''
*''Oligostema''
*''[[Biology:Hypericum sect. Olympia|Olympia]]''
*''Origanifolia''
*''[[Biology:Hypericum sect. Psorophytum|Psorophytum]]''
*''[[Biology:Hypericum sect. Roscyna|Roscyna]]''
*''Sampsonia''
*''[[Biology:Hypericum sect. Santomasia|Santomasia]]''
*''Taeniocarpium''
*''Takasagoya''
*''[[Biology:Hypericum sect. Triadenoides|Triadenoides]]''
*''[[Biology:Hypericum sect. Trigynobrathys|Trigynobrathys]]''
*''[[Biology:Hypericum sect. Tripentas|Tripentas]]''
*''[[Biology:Hypericum sect. Umbraculoides|Umbraculoides]]''
*''[[Biology:Hypericum sect. Webbia|Webbia]]''
{{div col end}}

==Ecology==
''H. perforatum'' is an [[Earth:Invasive species|invasive species]] and [[Biology:Noxious weed|noxious weed]] in farmland and gardens in the humid and sub-humid [[Earth:Temperate climate|temperate zones]] of several continents.<ref name=cabi/><ref name=usda/> It is considered [[Chemistry:Poison|poison]]ous to livestock.<ref name=cabi/>

Part of the invasive success of ''Hypericum'' species is due to the absence of natural pests.<ref name=cabi/> The [[Biology:Beetle|beetle]]s ''[[Biology:Chrysolina quadrigemina|Chrysolina quadrigemina]]'', ''[[Biology:Chrysolina hyperici|Chrysolina hyperici]]'' and the St. John's-wort root borer (''Agrilus hyperici'') feed on common St. John's-wort (''H.&nbsp;perforatum'') plants and have been used for biocontrol where the plant has become an invasive weed.<ref>{{Cite web|title = Ecology and Management of Common St. Johnswort {{!}} NRCS Montana|url = https://www.nrcs.usda.gov/wps/portal/nrcs/detail/mt/home/?cid=nrcs144p2_056716|website = www.nrcs.usda.gov|access-date = 2016-02-19}}</ref> ''Hypericum'' species are the only known food plants of the [[Biology:Caterpillar|caterpillar]] of the [[Biology:Treble-bar|treble-bar]], a species of [[Biology:Moth|moth]]. Other [[Biology:Lepidoptera|Lepidoptera]] species whose [[Biology:Larva|larva]]e sometimes feed on ''Hypericum'' include the [[Biology:Common emerald|common emerald]], the engrailed (recorded on imperforate St. John's-wort, ''H.&nbsp;maculatum''), the [[Biology:Grey pug|grey pug]] and the [[Biology:Setaceous Hebrew character|setaceous Hebrew character]].<ref>{{Cite journal|url = http://www.nhm.ac.uk/our-science/data/hostplants/search/list.dsml?PSpeciesqtype=starts+with&PSpecies=perforatum&PGenus=Hypericum&PFamilyqtype=starts+with&sort=Family&Familyqtype=starts+with&beginIndex=30&Speciesqtype=starts+with&Genusqtype=starts+with&PGenusqtype=starts+with&searchPageURL=index%2edsml%253FPSpeciesqtype%253Dstarts%252Bwith%2526PSpecies%253Dperforatum%2526PGenus%253DHypericum%2526PFamilyqtype%253Dstarts%252Bwith%2526sort%253DFamily%2526Familyqtype%253Dstarts%252Bwith%2526beginIndex%253D120%2526Speciesqtype%253Dstarts%252Bwith%2526Genusqtype%253Dstarts%252Bwith%2526PGenusqtype%253Dstarts%252Bwith%3fPSpeciesqtype%3dstarts%2bwith%26PSpecies%3dperforatum%26PGenus%3dHypericum%26PFamilyqtype%3dstarts%2bwith%26sort%3dFamily%26Familyqtype%3dstarts%2bwith%26beginIndex%3d0%26Speciesqtype%3dstarts%2bwith%26Genusqtype%3dstarts%2bwith%26PGenusqtype%3dstarts%2bwith|title = HOSTS-Search Results|access-date = 18 February 2016|website = HOSTS| date=2023 |publisher = [[Biology:Natural History Museum, London|Natural History Museum, London]]| doi=10.5519/havt50xw | last1=Robinson | first1=Gaden S. | last2=Ackery | first2=Phillip R. | last3=Kitching | first3=Ian | last4=Beccaloni | first4=George W. | last5=Hernández | first5=Luis M. }}</ref> A leaf beetle, ''Paria sellata'', feeds on the foliage of ''[[Biology:Hypericum adpressum|Hypericum adpressum]]'', while ant species ''[[Biology:Formica montana|Formica montana]]'' and ''[[Biology:Formica subsericea|F. subsericea]]'' decorate their nests with its bright yellow petals.<ref name=focr17 /> A small, reddish-brown weevil, ''Anthonomous rutilus''<!-- ''[[Biology:Anthonomus rutilus|Anthonomus rutilus]]''? --> breeds in the inflorescences of ''[[Biology:Hypericum kalmianum|Hypericum kalmianum]]'' and ''[[Biology:Hypericum swinkianum|H. swinkianum]]'', the larvae developing within the fruit capsules.<ref name=focr17 />

==Traditional medicine and adverse effects==
{{multiple image
 | total_width =300
 | image1 = Hyperforin.png
 | alt1 = Hyperforin
 | image2 = Hypericin.svg
 | alt2 = Hypericin
 | footer = [[Chemistry:Hyperforin|Hyperforin]] (left) and [[Chemistry:Hypericin|Hypericin]] (right)
}}
Common St. John's-wort (''H. perforatum'') has long been used in [[Medicine:Traditional medicine|traditional medicine]] as an [[Chemistry:Extract|extract]] to treat [[Medicine:Depression (mood)|depression]].<ref name="nccih">{{cite web |title=St. John's wort and depression: in depth |url=https://nccih.nih.gov/health/stjohnswort/sjw-and-depression.htm |publisher=National Center for Complementary and Integrative Health, US National Institutes of Health |access-date=22 February 2019 |date=1 December 2017}}</ref> ''H. perforatum'' is the most commonly used species &ndash; especially in Europe &ndash; as an herbal substitute for [[Medicine:Prescription drug|prescription drug]]s to treat depression, and is also sold as a dietary supplement.<ref name=nccih/> One [[Meta-analysis|meta-analysis]] found that St John's wort had similar efficacy and safety as prescriptions drugs to treat mild-to-moderate depression, such as [[Chemistry:Selective serotonin reuptake inhibitor|selective serotonin reuptake inhibitor]]s.<ref name="pmid28064110">{{cite journal |vauthors=Ng QX, Venkatanarayanan N, Ho CY |title=Clinical use of ''Hypericum perforatum'' (St John's wort) in depression: A meta-analysis |journal=J Affect Disord |volume=210 |pages=211–221 |date=1 March 2017 |pmid=28064110 |doi=10.1016/j.jad.2016.12.048 }}</ref>

There is evidence that combining St. John’s wort with prescription [[Chemistry:Antidepressant|antidepressant]]s may cause [[Medicine:Adverse effect|adverse effect]]s, such as a life-threatening increase of [[Chemistry:Serotonin|serotonin]], the brain chemical targeted by some drugs used for depression.<ref name=nccih/> Symptoms may include agitation, [[Medicine:Diarrhea|diarrhea]], high [[Physics:Blood pressure|blood pressure]], and [[Unsolved:Hallucination|hallucination]]s.<ref name=nccih/>  Taking St. John’s wort may interfere with and reduce the efficacy of prescription drugs used to treat depression.<ref name=nccih/>

St. John's wort interacts with hormonal contraceptives, reducing their effectiveness and increasing the risk of unplanned pregnancy.<ref>{{cite web|url=https://www.gov.uk/drug-safety-update/st-john-s-wort-interaction-with-hormonal-contraceptives-including-implants|title=St John's wort: interaction with hormonal contraceptives, including implants|date=11 December 2014|publisher=Drug Safety, Gov.UK|access-date=15 August 2022 }}</ref>

==Ornamental plants== 
[[File:Hypericum olympicum Liberec 1.jpg|thumb|right|''Hypericum olympicum'' in Botanic garden Liberec]]Some species are used as ornamental plants as many have large, showy flowers. Species found in cultivation include:<ref name=RHSAZ>{{cite book | editor-last = Brickell | editor-first = Christopher | title = The Royal Horticultural Society A-Z Encyclopedia of Garden Plants | year = 2008 | page = 302 | publisher = Dorling Kindersley | location = United Kingdom | isbn = 9781405332965}}</ref> 
{{div col|colwidth=22em}}
*''[[Biology:Hypericum aegypticum|H. aegypticum]]''
*''[[Biology:Hypericum androsaemum|H. androsaemum]]''
*''[[Biology:Hypericum balearicum|H. balearicum]]''
*''[[Biology:Hypericum bellum|H. bellum]]''
*''[[Biology:Hypericum calycinum|H. calycinum]]''
*''[[Biology:Hypericum elodes|H. elodes]]''
*''[[Biology:Hypericum forrestii|H. forrestii]]''
*''[[Biology:Hypericum kalmianum|H. kalmianum]]''
*''[[Biology:Hypericum kouytchense|H. kouytchense]]''
*''[[Biology:Hypericum olympicum|H. olympicum]]''
*''[[Biology:Hypericum perforatum|H. perforatum]]''
{{div col end}}

Numerous [[Biology:Hybrid|hybrids]] and [[Biology:Cultivar|cultivar]]s have been developed for use in [[Earth:Horticulture|horticulture]]. The following have gained the Royal Horticultural Society's Award of Garden Merit:
* ''H.'' × ''moserianum''<ref name="RHS-2020-1">{{cite web|title = Hypericum × moserianum|url = https://www.rhs.org.uk/Plants/89802/Hypericum-x-moserianum/Details |publisher = Royal Horticultural Society|access-date = 8 September 2020}}</ref> (''[[Biology:Hypericum calycinum|H.&nbsp;calycinum]]'' × ''[[Biology:Hypericum patulum|H.&nbsp;patulum]]'')
* 'Hidcote'<ref name="RHS-2020-2">{{cite web|title = Hypericum × hidcoteense 'Hidcote'|url = https://www.rhs.org.uk/Plants/332180/Hypericum-x-hidcoteense-Hidcote/Details |publisher = Royal Horticultural Society|access-date = 8 September 2020}}</ref> 
* 'Rowallane'<ref name="RHS-2020-3">{{cite web|title = Hypericum 'Rowallane'|url = https://www.rhs.org.uk/Plants/97331/Hypericum-Rowallane/Details |publisher = Royal Horticultural Society|access-date = 8 September 2020}}</ref>

Most species of Hypericum are prone to thrips, scale, anthracnose, rust, and leaf spots.<ref name="www.finegardening.com st-johns-wort-hypericum">[http://www.finegardening.com/st-johns-wort-hypericum Fine Gardening] Retrieved November 23, 2015.</ref> They are also eaten or infected by aphids,  white flies, and [[Biology:Spodoptera littoralis|spodoptera littoralis]].<ref>[http://www.danziger.co.il/files/b09bd83176b3a0e0edab5345bba1e2d8.pdf Dan Ziger Corporation] Retrieved November 30, 2015.</ref>

==Fossil record==
The oldest fossil species is †''[[Biology:Hypericum antiquum|Hypericum antiquum]]'' from the [[Earth:Eocene|Eocene]] of Siberia.<ref name="mobot" /> Fossil seeds from the early Miocene of †''Hypericum septestum'' have been found in the [[Place:Czech Republic|Czech]] part of the Zittau Basin.<ref>Acta Palaeobotanica - 43(1): 9-49, January 2003 - Early Miocene carpological material from the Czech part of the Zittau Basin - Vasilis Teodoridis</ref> Many [[Biology:Fossil|fossil]] seeds of †''Hypericum holyi'' have been described from [[Earth:Middle Miocene|middle Miocene]] strata of the Fasterholt area near Silkeborg in Central Jutland, {{wipe|Denmark}}.<ref>Angiosperm Fruits and Seeds from the Middle Miocene of Jutland (Denmark) by Else Marie Friis, The Royal Danish Academy of Sciences and Letters 24:3, 1985</ref>

==References==
{{Reflist|refs=
<ref name=powo>{{cite web |title=''Hypericum'' Tourn. ex L. |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30002180-2 |website=Plants of the World Online |publisher=[[Organization:Royal Botanic Gardens, Kew|Royal Botanic Gardens, Kew]] |access-date=30 September 2020}}</ref>
}}

==External links==
*{{cite web |url = http://hypericum.myspecies.info |title= Hypericum Online}}

{{Taxonbar|from=Q156935}}

[[Category:Hypericum| ]]
[[Category:Malpighiales genera]]

{{Sourceattribution|Hypericum}}