Fact-checked by Grok 2 weeks ago

Hypericum

Hypericum is a genus of approximately 490 species of flowering plants in the family Hypericaceae, commonly known as St. John's worts.^[1] These plants are predominantly distributed in temperate regions worldwide, with additional occurrences in montane areas of the tropics, and are absent from Antarctica, polar regions, deserts, and tropical lowlands.^[2]^[1] The genus exhibits diverse growth forms, ranging from herbaceous perennials and subshrubs to small trees, with stems often two-ridged and leaves opposite, simple, and elliptic to oblong.^[3] A distinctive feature of Hypericum species is the presence of translucent and dark glandular dots or lines on leaves, petals, and sepals, which contain hypericin and other compounds responsible for the characteristic punctiform patterns and red pigmentation when crushed.^[3] Flowers are typically yellow, with five sepals and petals, and numerous stamens fused into five bundles, blooming primarily in summer.^[3] Ecologically, Hypericum species thrive in a variety of open habitats, including meadows, grasslands, roadsides, and forest edges, often preferring well-drained, sunny sites.^[4] Many are adapted to nutrient-poor soils and can act as pioneers in disturbed areas, with some, like H. perforatum, considered invasive in non-native regions due to their prolific seed production and vegetative spread.^[2] Hypericum holds significant economic and medicinal value; H. perforatum (common St. John's wort) is widely used in herbal medicine for its antidepressant, anti-inflammatory, and antimicrobial properties, attributed to bioactive compounds like hyperforin and hypericin.^[2] Numerous species are cultivated as ornamentals for their attractive flowers and foliage, while others contribute to biodiversity in native ecosystems.^[1] The taxonomy of the genus has been extensively studied, notably through Norman Robson's monographs, highlighting its evolutionary diversity across sections and subsections.^[1]

Botanical Characteristics

Morphology

Hypericum species display a diverse array of growth habits, ranging from perennial herbs and subshrubs to shrubs and, less commonly, small trees, with heights typically spanning 0.2 to 5 meters depending on the taxon.^[5] Stems are erect or ascending, often woody at the base in shrubby forms, and characterized by internodes that are initially terete or 2-, 4-, or 6-lined due to raised vascular tissues, later becoming angled, winged, or smooth; these lines result from internal phloem strands positioned opposite the decussate leaves.^[5]^[3] Leaves in the genus are opposite, simple, and entire-margined, usually sessile or with short petioles, and elliptic to oblong in shape, measuring 0.5–5 cm in length; they often persist or are deciduous and feature translucent dot-like glands or lacunae filled with essential oils or resins.^[5]^[3] In many species, these glands impart a characteristic spotted or dotted appearance, particularly visible when held to light, aiding in identification.^[3] Flowers are borne in terminal or axillary cymes, forming compact or open inflorescences, and consist of five persistent sepals that are free or slightly connate, often glandular-ciliate, and five golden-yellow petals (rarely white or orange-tinged) that are contorted and measure 0.5–4 cm long.^[5]^[3] The androecium includes numerous stamens (10–300 or more) arranged in three to five fascicles, with yellow to orange anthers bearing amber or black glands; the gynoecium features a superior, 2–5-merous ovary (most commonly three-locular) with axile placentation and three free or basally connate styles terminating in capitate or peltate stigmas.^[5]^[3] Fruits are dry, septicidal capsules that dehisce from the apex into 2–5 valves (typically three), revealing small (0.3–1.5 mm), brown, narrowly cylindric to ellipsoid seeds with a foveolate or reticulate testa; capsule morphology varies from ovoid to cylindrical or broadly ellipsoid across species.^[5]^[3] Key diagnostic traits include the presence of two types of glands: pale, translucent ones containing oils or phloroglucinols, and dark, punctiform glands rich in hypericin (a naphthodianthrone pigment) on leaves, petals, sepals, and sometimes stems, notably in species like Hypericum perforatum where black dots on petal margins and leaf undersides are prominent.^[3] These glandular features, along with stem lining and stamen fasciculation, contribute to morphological distinctions used in taxonomic classification.^[3]

Reproduction

Hypericum species primarily reproduce sexually through hermaphroditic flowers that are pollinated by insects such as bees and flies.^[6] These flowers feature five yellow petals and numerous stamens, which facilitate pollen transfer during insect visitation.^[7] Flowering typically occurs in summer within temperate regions, aligning with peak insect activity for effective pollination.^[8] Following pollination, Hypericum produces dehiscent capsules containing numerous small seeds, with high output observed in species like H. perforatum, where a single plant can generate 15,000 to 33,000 seeds annually.^[9] Seed dispersal occurs via multiple mechanisms, including short-distance wind transport, adhesion to animal fur or feathers, water movement, and limited ballistic ejection from drying capsules.^[10] Seeds demonstrate long-term viability, remaining dormant in soil seed banks for over 10 years and up to 50 years in some cases, contributing to persistent populations.^[9] Asexual reproduction in Hypericum occurs through vegetative propagation in certain species, such as rhizomatous spread in H. perforatum under stressful conditions and rooting of stems in H. androsaemum.^[9] Apomixis, an asexual seed formation bypassing fertilization, is rare but documented as facultative in lineages like H. perforatum, where up to 97% of ovules may develop aposporously.^[7] The life cycle of Hypericum varies by species, encompassing annual, biennial, and predominantly perennial habits, with H. perforatum exemplifying a perennial forb that flowers in its second year.^[9] Germination requires light exposure, moist conditions, and often a dormancy-breaking period such as after-ripening or alternating temperatures to achieve rates up to 81%.^[9]

Taxonomy and Classification

Etymology and History

The genus name Hypericum derives from the ancient Greek words hyper (above) and eikon (picture), alluding to the position of the flowers above the leafy bracts or to the ancient custom of suspending the plant's flowers over religious icons or images to ward off evil spirits.^[11] This etymology reflects early cultural associations with protection and ritual, as the plants were often used in midsummer ceremonies. Folk names such as "St. John's wort" arose from the plant's typical blooming period around June 24, coinciding with the Christian feast of St. John the Baptist (Midsummer's Day), when the golden-yellow flowers were harvested for protective charms against malevolent forces.^[12] References to Hypericum species appear in ancient literature, notably in Pedanius Dioscorides' De Materia Medica (circa 50–70 AD), where the plant—known as hyperikon—was described for its medicinal properties, including wound healing and as a diuretic, marking one of the earliest documented recognitions of the genus.^[13] The genus received formal taxonomic description in Carl Linnaeus's Species Plantarum (1753), where he established Hypericum as a distinct entity within the plant kingdom, encompassing numerous species based on morphological traits like opposite leaves and clustered flowers.^[14] Early botanical efforts, however, involved taxonomic confusion, particularly with the related genus Ascyrum; for instance, Linnaeus initially classified some North American species resembling Hypericum under Ascyrum hypericoides in the 18th century, reflecting uncertainties in delimiting genera before later reassignments.^[15] Explorations in the 19th century significantly expanded knowledge of Hypericum diversity, especially in the New World; botanist Thomas Nuttall, during his travels across North America from 1810 to 1841, documented and described several species, contributing to the recognition of regional variations and aiding in the genus's broader circumscription. Major advancements in the 20th century came through the systematic revisions by Norman K. B. Robson, whose series of studies beginning in 1977—published in the Bulletin of the British Museum (Natural History), Botany—redefined infrageneric classifications, resolved longstanding sectional ambiguities, and laid the foundation for contemporary understanding of the genus through the 2010s.^[14]

Subdivisions and Species

The genus Hypericum encompasses approximately 490 species classified into 36 sections, reflecting a nearly worldwide distribution primarily in temperate regions and montane areas of the tropics, with centers of diversity in the Northern Hemisphere.^[14] This infrageneric framework, established through morphological revisions, highlights the genus's diversity in growth forms ranging from herbs to shrubs and small trees. Recent molecular phylogenies, such as those based on nuclear and plastid DNA sequences, have shown that the traditional circumscription of Hypericum is not monophyletic, with the genus Triadenum embedded within it—suggesting that Hypericum should include Triadenum to achieve monophyly—while indicating rearrangements in sectional boundaries due to convergent traits like gland distribution and capsule morphology.^[16] Key sections illustrate the genus's biogeographic patterns and morphological variation. Section Hypericum, the type section, comprises Eurasian temperate species characterized by punctate leaves and stems with two lines of glands; it includes around 40 species, many adapted to meadow and forest edge habitats.^[3] Section Adenotrias, a small Mediterranean endemic group with three species (H. aciferum, H. aegypticum, and H. russeggeri), features eglandular petals and prostrate shrubs on rocky limestone substrates, forming a basal clade in phylogenetic analyses.^[3] Section Brathys, the largest with over 100 New World species, consists of shrubs and herbs in high-elevation Andean and North American montane regions, distinguished by capitate stigmas and often explosive diversification patterns.^[17] Other primary sections include Androsaemum (Eurasian shrubs with persistent calyces, ~10 species), Ascyreia (Asian evergreen shrubs with large flowers, ~50 species), Campylosporus (African tropical species with revolute leaves, ~20 species), Myriandra (New World herbs and subshrubs, ~30 species), and Trigynobrathys (South American shrubs with three styles, ~40 species), each tied to distinct geographic foci and adaptive traits like stem anatomy for water storage in arid zones.^[14] Notable species exemplify sectional diversity and human interactions. Hypericum perforatum (common St. John's wort), in section Hypericum, is a rhizomatous perennial herb native to Eurasia but invasive in North American grasslands and pastures, where it forms dense stands reducing forage quality.^[18] Hypericum calycinum (Aaron's beard), from section Ascyreia, is a low-growing evergreen shrub from western Asia, valued for its large golden flowers and use as an ornamental groundcover in temperate gardens. Hypericum androsaemum (tutsan), in section Androsaemum, is a Eurasian deciduous shrub with copper-toned berries, occurring in woodland understories and sometimes naturalized in North America.^[19] Endemics like Hypericum revolutum (curry bush), in section Campylosporus, is an African shrub restricted to montane forests and scrub in eastern and southern regions, featuring aromatic leaves and red-tinged branches. Infrageneric classification faces challenges from frequent hybridization and polyploidy, which blur species boundaries and complicate delimitation, particularly in Eurasian and Andean clades where reticulate evolution has led to cryptic gene pools and variable ploidy levels (diploid to hexaploid).^[20] These factors, evident in complexes like H. perforatum, necessitate integrated morphological and molecular approaches for accurate taxonomy.^[21]

Distribution and Ecology

Geographic Range

The genus Hypericum exhibits a cosmopolitan native distribution, occurring on all continents except Antarctica, with a particular concentration in temperate regions of the Northern Hemisphere and montane habitats in the tropics.^[2] The highest species diversity is found in the Mediterranean Basin, where more than 150 of the approximately 500 recognized species occur, representing over 60% of the genus's sectional diversity and including numerous endemics such as those in sections Hirtella and Psorophytum.^[3]^[4] In eastern North America, around 58 species are native, many concentrated in the southeastern United States, while Europe hosts significant diversity, particularly in western and southern regions.^[22]^[23] Eastern Asia's mountains, especially in China, support about 75 species, 39 of which are endemic.^[2]^[24] Disjunct patterns are evident, with temperate lineages contrasting against tropical montane occurrences, such as in the Andean páramos. Several Hypericum species have been widely introduced outside their native ranges, often becoming invasive. H. perforatum, native to Europe, western Asia, and northern Africa, was first recorded in North America in 1793 in Pennsylvania and spread rapidly across western states by the early 1900s, infesting millions of acres in California, Idaho, Oregon, and Washington through agricultural and ornamental pathways.^[10] It was introduced to Australia in the 19th century, initially along streams during gold mining activities, and to New Zealand around the 1860s–1870s as a garden plant, subsequently establishing in temperate areas and requiring biological control efforts.^[10] Biogeographically, Hypericum traces its origins to the Holarctic region, with stem-lineages present before crown-group diversification in the Late Eocene (~33.9 Ma), facilitated by climatic corridors like Beringia.^[25] Subsequent radiations extended into southern continents, including explosive diversification in South America's Andean páramos around 3.3–3.8 Ma, linked to tectonic uplift.^[17] The genus spans a broad altitudinal gradient, from sea level in temperate zones to over 4,500 m in the Andes, where páramo endemics like those in the Brathys clade dominate high-elevation ecosystems.^[17] Endemism hotspots underscore regional biodiversity patterns, with the Mediterranean Basin featuring high levels of narrow-range species, such as H. balearicum in the Balearic Islands.^[3] The California Floristic Province also hosts notable endemism, including species like H. concinnum restricted to coastal and montane areas, contributing to the province's status as a global hotspot.^[22]

Habitat and Interactions

Species of the genus Hypericum predominantly inhabit open, sunny environments that provide ample light for photosynthesis and growth, including meadows, roadsides, forest edges, and rocky slopes. These plants thrive in well-drained soils ranging from acidic to neutral pH, often in areas with moderate moisture but tolerance for drier conditions once established. For instance, Hypericum perforatum is commonly found in grasslands, pastures, and disturbed sites such as rangelands, where it prefers full sun exposure and sandy or loamy soils. In Mediterranean climates, certain species adapt to fire-prone chaparral ecosystems in California, where they exhibit resprouting or seeding strategies post-fire to recolonize disturbed areas rapidly.^[10]^[26]^[27] Biotic interactions play a crucial role in the ecology of Hypericum species. Mutualistic relationships with pollinators are prominent, as the bright yellow flowers of H. perforatum attract a variety of insects, particularly bees that collect abundant pollen, though the plant produces no nectar. Herbivory is deterred by secondary metabolites like hypericin, which induces phototoxicity in grazing livestock upon ingestion, causing skin irritation under sunlight and thereby reducing browsing pressure. Many Hypericum species form arbuscular mycorrhizal associations that enhance nutrient uptake, particularly phosphorus, in nutrient-poor soils.^[9]^[28]^[29] Competition occurs with co-occurring grasses and other invasives, where Hypericum can alter resource availability through dense growth forms.^[9] Ecologically, Hypericum contributes to soil stabilization on slopes and disturbed terrains by forming root networks that prevent erosion in rocky or sandy habitats. As invasives, species like H. perforatum outcompete native plants in grasslands and open woodlands, forming monocultures that reduce local biodiversity by shading out understory species and altering soil chemistry. In temperate regions, these plants serve as pioneers in successional habitats, facilitating community recovery after disturbances. Tropical montane species occupy cloud forest edges and páramo grasslands, where they interact with high-altitude pollinators and contribute to habitat structure in misty, humid environments. Climate factors influence persistence, with temperate Hypericum species showing vulnerability to prolonged droughts that limit growth in drier meadows, while montane taxa in cloud forests benefit from consistent moisture but face risks from shifting precipitation patterns.^[10]^[30]^[31]^[26]

Human Uses

Medicinal Applications

Hypericum species, particularly H. perforatum (St. John's wort), have been employed in traditional medicine since ancient times for treating wounds, inflammation, and mood disorders. Records from the 5th century BC indicate that Hippocrates recommended it for wound healing and as an anti-inflammatory agent. In European folk medicine, it served as a nervine to alleviate anxiety and depression, as well as a diuretic for urinary issues.^[32]^[33]^[34] The primary active compounds in H. perforatum include hypericin, hyperforin, and flavonoids, which are concentrated in the plant's glandular structures. Hyperforin is considered the key constituent for antidepressant effects, acting by inhibiting the reuptake of serotonin, norepinephrine, and dopamine, mechanisms akin to selective serotonin reuptake inhibitors (SSRIs). Hypericin contributes to antiviral and anti-inflammatory properties, though its role in mood regulation is less direct. Flavonoids provide additional antioxidant support.^[34]^[35]^[36] Clinical trials since the 1990s have demonstrated the efficacy of H. perforatum extracts for mild to moderate depression, with response rates comparable to standard antidepressants like SSRIs and superior to placebo. A 1996 meta-analysis of 23 randomized trials involving 1,757 patients confirmed its benefits, with response rates 23% to 55% higher than placebo. More recent meta-analyses, such as those from 2017 and 2023, continue to support its efficacy for mild to moderate depression comparable to SSRIs with fewer adverse effects, though results vary by extract quality. Standardized oral extracts, typically containing 0.3% hypericin (e.g., 300 mg doses three times daily), are commonly used in these studies. In Europe, the European Medicines Agency (EMA) recognizes well-established use for treating mild to moderate depressive episodes based on clinical evidence, while it is available over-the-counter in the US as a dietary supplement with FDA warnings on labeling.^[37]^[38]^[39]^[34]^[40]^[41]^[42] Topically, H. perforatum oils and tinctures are applied for minor burns, wounds, and herpes simplex virus (HSV) lesions, reducing pain, erythema, and healing time in trials. These applications leverage the plant's anti-inflammatory and antiviral compounds produced in its morphological glands.^[43]^[44] Adverse effects of H. perforatum are generally mild but include photosensitivity, leading to heightened sunburn risk due to hypericin's photodynamic properties. Common reactions also encompass gastrointestinal upset, fatigue, dizziness, and dry mouth. It induces cytochrome P450 3A4 (CYP3A4) enzymes and P-glycoprotein, reducing efficacy of drugs like oral contraceptives, anticoagulants (e.g., warfarin), and antiretrovirals, potentially causing breakthrough bleeding or treatment failure. Contraindications include bipolar disorder, where it may precipitate mania or rapid cycling. Overdose risks involve severe gastrointestinal distress and confusion.^[45]^[46]^[47]^[48]^[49]^[50]

Ornamental and Other Uses

Hypericum species are valued in ornamental horticulture for their vibrant yellow flowers, attractive foliage, and versatile growth habits, making them suitable for various garden settings. Low-growing species such as Hypericum calycinum, known as Aaron's beard, serve as effective evergreen groundcovers, thriving in shaded or dry areas with their deep green oval leaves and golden blooms from late spring to early summer.^[51] Similarly, Hypericum olympicum is prized for rock gardens and border fronts due to its compact, mounding form and pale lemon-yellow flowers that appear in midsummer on grey-green foliage.^[52] Hybrid cultivars like 'Hidcote', a compact deciduous shrub reaching 3-4 feet tall, are commonly planted in borders for their profuse, large golden-yellow flowers from June to August, providing seasonal interest with their bushy habit.^[53] Cultivation of Hypericum is straightforward, with propagation typically achieved through seeds sown in spring or semi-hardwood cuttings taken in late summer, rooting readily in well-drained media. These plants prefer full sun to partial shade and moist, well-drained soils, tolerating a range of conditions including clay and alkaline types once established, though they perform best with moderate watering to avoid waterlogging. Most species are hardy in USDA zones 5-9, with shrubby forms like 'Hidcote' benefiting from annual pruning in early spring to promote flowering on new growth and maintain shape. Common pests include rust fungi such as Melampsora hypericorum, which cause orange pustules on leaves; management involves pruning infected parts, improving air circulation, and avoiding overhead watering, with fungicides like myclobutanil applied preventively if needed in humid climates.^[54]^[55]^[56]^[57] Beyond ornamentals, Hypericum finds practical applications in dye production, where flowers yield yellow to red hues when simmered or fermented, historically used for textiles in traditional crafts. In agriculture, it can serve as livestock fodder in limited quantities, though overconsumption risks phototoxicity leading to skin inflammation in grazing animals like cattle and sheep, necessitating careful monitoring to prevent exposure to sunlight after ingestion. Culturally, Hypericum holds symbolic significance in folklore as a protector against evil spirits, often incorporated into midsummer wreaths or hung over doorways during St. John's Day celebrations to ward off misfortune and promote good luck. Economically, while commercial cultivation supports ornamental nurseries, harvesting for non-medicinal products like dyes remains niche; however, invasive Hypericum species incur management costs, with biocontrol programs in regions like New Zealand yielding benefits exceeding NZ$15 million annually through reduced control expenses.^[58]^[59]^[60]^[61]

Evolutionary History

Fossil Record

The fossil record of Hypericum extends from the Late Eocene to the present, providing evidence of the genus's ancient diversification primarily through seeds, pollen, and occasional vegetative remains. The earliest confirmed fossils are seeds of Hypericum antiquum, discovered in Upper Eocene deposits (approximately 35–40 million years ago) in West Siberia, northern Asia. These cylindrical, reticulate seeds closely resemble those of modern Hypericum species and mark the initial appearance of the genus in the paleobotanical record, indicating an early divergence within the Hypericaceae family during a period of boreotropical forest expansion.^[62] In North America, direct fossil evidence remains limited, though Paleogene pollen records suggest possible early occurrences amid the surprising scarcity of macrofossils despite the region's modern species diversity. By the Oligocene (approximately 33–23 million years ago), the record becomes more diverse, with seed impressions of species like Hypericum septestum and Hypericum bornense reported from strata in Germany and Russia, alongside fossil pollen grains attributed to Hypericum from deposits in the Ebro Basin in Spain; these fossils, often preserved in lacustrine sediments, provide the first clear evidence of leaf and fruit-like structures, reflecting adaptations to increasingly temperate conditions.^[63]^[62]^[64] Key discoveries further illuminate the genus's paleobiology, including Miocene (approximately 23–5 million years ago) seed fossils from Asia, such as those akin to forms in the modern section Brathys, found in East Asian deposits that suggest continuity with high-elevation lineages. These Asian Miocene remains, alongside European examples like Hypericum miocenicum from Late Oligocene to Early Miocene sites in Germany, indicate widespread distribution during a time of global cooling and tectonic reconfiguration. No Hypericum fossils have been identified in Baltic amber from the Eocene, though the amber's preservation of contemporaneous flora underscores the genus's association with humid, subtropical environments.^[62]^[65] The distribution of these fossils supports a Laurasian origin for Hypericum, with the genus likely emerging in northern temperate zones before dispersing southward to Gondwanan landmasses via boreotropical corridors across the North Atlantic and Tethys Sea during the Eocene-Oligocene transition. This pattern aligns with post-Cretaceous adaptations to cooling climates, including the evolution of cold tolerance around 30 million years ago, which facilitated colonization of diverse habitats and accelerated diversification in the Miocene. Fossil evidence from northern Asia and Europe reinforces this northern cradle, while southern records imply long-distance dispersal rather than vicariance.^[66]^[67] Despite this richness in Cenozoic records, significant gaps persist, particularly in the Mesozoic era, where no definitive Hypericum fossils have been documented, limiting direct insights into the family's pre-Eocene history. Inferences for earlier origins rely heavily on pollen data and phylogenetic calibrations, as macrofossils are absent before the Late Eocene; additionally, the underrepresentation of North American fossils highlights potential biases in preservation or sampling.^[62]^[65]

Conservation Status

Several Hypericum species face conservation challenges, with a subset assessed as threatened on the IUCN Red List or national endangered species lists, reflecting vulnerabilities in their often restricted ranges. For instance, Hypericum gnidiifolium is classified as Critically Endangered due to its occurrence at only two locations in Ethiopia, where ongoing habitat degradation limits its persistence. Similarly, Hypericum asplundii is Endangered in Ecuador, primarily owing to habitat loss in montane ecosystems. Other examples include Hypericum balfourii, Vulnerable in Yemen from limited distribution and land-use pressures, and Hypericum socotranum, Endangered in the Socotra archipelago due to overgrazing and development. In the United States, Hypericum cumulicola is federally listed as Endangered, with populations confined to Florida's Lake Wales Ridge scrub habitat.^[68] These cases highlight that while most of the approximately 500 species remain unassessed globally, endemics—particularly in Mediterranean, Andean, and insular regions—represent a disproportionate risk, with regional assessments indicating vulnerabilities for taxa in California and elsewhere due to narrow distributions. Major threats to Hypericum species stem from anthropogenic habitat destruction, including agricultural expansion and urban development, which fragment specialized ecosystems like coastal scrubs and montane grasslands. For example, mining and residential growth have severely impacted Hypericum cumulicola populations in Florida, reducing suitable sandy habitats.^[69] Overharvesting for medicinal purposes exacerbates declines in wild populations, as seen with Hypericum sinaicum in Egypt's South Sinai, where collection for traditional remedies affects over 24% of known sites.^[70] Invasive congeners, such as Hypericum perforatum, further threaten native taxa through competition in disturbed areas. Climate change poses an additional risk by altering montane niches, potentially shifting distributions and increasing drought vulnerability for species like Hypericum elodes in Europe.^[71] Conservation efforts focus on habitat protection and species recovery, with many at-risk Hypericum integrated into protected areas such as national parks and reserves. In Florida, Hypericum cumulicola benefits from management at sites like Archbold Biological Station, where prescribed fire maintains scrub habitat and supports population stability across 22 protected locations.^[69] Ex situ strategies, including propagation in botanic gardens and seed banking, aid recovery; for instance, Missouri Botanical Garden has stored Hypericum adpressum seeds to preserve genetic material from wetland populations.^[72] In the Mediterranean and Middle East, initiatives for Hypericum sinaicum involve sustainable harvesting quotas, feral animal control, and promotion of cultivation to reduce wild collection pressures within the Saint Katherine Protectorate.^[70] No Hypericum species are currently listed under CITES, though rare endemics are monitored for potential inclusion. Ongoing research emphasizes genetic diversity assessments to inform breeding programs and restoration, particularly for fragmented populations vulnerable to inbreeding. Projects targeting native analogs of invasives aim to restore ecological balance, while broader studies on climate resilience are needed to predict and mitigate range shifts in montane Hypericum taxa.^[71]

References

[1]
Hypericum online | A site dedicated to Hypericum – The St John's ...
Hypericum is a genus of 490 species of flowering plants in the family Hypericaceae. Hypericum includes St John's Wort (H. perforatum L.), an economically ...Nomenclature · Literature · Media gallery · About us
[2]
Hypericum Genus as a Natural Source for Biologically Active ... - NIH
Sep 26, 2022 · Hypericum L. genus plants are distributed worldwide, with numerous species identified throughout all continents, except Antarctica.
[3]
Morphological and Phytochemical Diversity among Hypericum ...
Depending on the species and in some cases the age of the plant, 2, 4 or 6 ridges may be observed, or the stem may appear terete. Both pale and dark glands may ...
[4]
Hypericum - an overview | ScienceDirect Topics
This genus is distributed worldwide, especially in temperate regions of the Northern Hemisphere. Hypericum species can also be found in tropical and warm ...
[5]
Hypericum - FNA - Flora of North America
Nov 5, 2020 · Stems: internodes terete (not lined) or 2-, 4-, or 6-lined at first (lines usually raised), then sometimes becoming angled, terete, or winged; ...Missing: two- | Show results with:two-
[6]
Corolla chirality does not contribute to directed pollen movement in ...
Jun 26, 2016 · We quantified pollen transfer and pollinator behavior and movement for both right and left rotated flowers in two populations of Hypericum ...
[7]
[PDF] Reproduction Mode in Hypericum and its Consequences
In the genus Hypericum all three fundamental reproduction modes have been described. Besides outcrossing sex, self compatibility is widespread in the genus ( ...
[8]
Hypericum perforatum (Common St. John's-wort, Goatweed ...
Flower Bloom Time: Spring: Summer; Flower Petals: 4-5 petals/rays; Flower Size: 1-3 inches; Flower Description: Yellow petals with black dots on margins; bushy ...
[9]
[PDF] Common St. Johnswort (Hypericum perforatum) Plant Guide
Each plant produces roughly 15,000-33,000 seeds and the seeds numbered 580,000 per ounce. Seeds remain viable in the soil for long periods of time; as much as ...
[10]
Species: Hypericum perforatum
Seed banking: Some authors suggest that seeds of Hypericum species remain viable in the soil for periods longer than 50 years ([191] and references therein).
[11]
https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=279207
[12]
#PlantoftheMonth: Saint John's Wort | McClung Museum of Natural ...
Apr 22, 2022 · However, Common Saint John's Wort (Hypericum perforatum) is non-native, introduced from native origins such as Europe, North Africa, and western ...Missing: etymology | Show results with:etymology
[13]
[PDF] Intriguing World of Weeds - UC ANR Portal
In 1753, Carolus Linnaeus described Hypericum perfo- ratum in Species Plantarum. Dioscorides knew the plant as Hyperikon, the old Greek name, believed to be ...
[14]
[PDF] the monograph of Hypericum by Norman Robson - Phytotaxa
May 14, 2010 · With about 470 species Hypericum Linnaeus (1753) is one of the 100 large angiosperm genera that collectively comprise an estimated 22% of ...
[15]
Plant Names Tell Their Stories: Hypericum spp. (St. John's wort)
Jun 13, 2022 · The genus Hypericum has a memorable etymology from the Greek: hyper, meaning “above” and eikon, meaning “image,” referring to the practice of hanging these ...
[16]
[PDF] Hypericum robsonii spec. nova sect. Trigynobrathys (Hypericaceae ...
The flowering plant genus Hypericum L. is currently divided into 36 taxonomic sections and encompasses approximately 490 species that are distributed in ...<|separator|>
[17]
Bayesian inference of phylogeny, morphology and range evolution ...
Hypericum L. represents one of the 100 largest angiosperm genera of the world (Carine and Christenhusz, 2010), with over 496 species (including other Hypericeae ...
[18]
Explosive radiation in high Andean Hypericum—rates of ... - Frontiers
Sep 10, 2013 · The majority of New World Hypericum is classified in sects. Brathys and Trigynobrathys (Table 1). Although predominately a high-elevation group ...
[19]
Common St. John's Wort (Hypericum perforatum) - iNaturalist
Hypericum perforatum, also known as common St John's wort, is a medicinal herb with antidepressant and anti-inflammatory properties.Missing: morphology botanical<|control11|><|separator|>
[20]
Hypericum calycinum - Wikipedia
Hypericum calycinum ; Order: Malpighiales ; Family: Hypericaceae ; Genus: Hypericum ; Section: H. · sect. Ascyreia.
[21]
Hypericum androsaemum (Sweet-amber) - FSUS
Section: Androsaemum. ; Common name: Sweet-amber, Tutsan. ; Phenology: May-Aug. ; Habitat: Old fields, disturbed areas (commonly cultivated). ; Distribution: Native ...
[22]
Hypericum revolutum - Wikipedia
Hypericum revolutum ; Order: Malpighiales ; Family: Hypericaceae ; Genus: Hypericum ; Section: Hypericum sect. Camplyosporus.
[23]
Evolution of cryptic gene pools in Hypericum perforatum
Mar 26, 2013 · Hypericum maculatum is thought to comprise two diploid subspecies (subsp. maculatum and subsp. immaculatum) and a tetraploid subspecies (subsp.Missing: challenges | Show results with:challenges
[24]
Mixed-Ploidy and Dysploidy in Hypericum perforatum - MDPI
Hypericum perforatum is commonly a tetraploid species with the basic chromosome number of x = 8 [21], although diploid (2x), triploid (3x) and hexaploid (6x) ...
[25]
Hypericum in Flora of North America @ efloras.org
Shrubs with deciduous leaves, petals, and stamens belong to either Hypericum sect. Ascyreia Choisy (with five stamen fascicles and five styles) or sect.<|control11|><|separator|>
[26]
(PDF) Integrating Fossils, Phylogenies, and Niche Models into ...
Nov 14, 2014 · To show the power of this approach, we reconstruct the biogeographic history of the large angiosperm genus Hypericum, which has a fossil record ...
[27]
Hypericum species in the Páramos of Central and South America
High altitude vegetation habitats (Páramos) in Central and South America are home to numerous native Hypericum species. Information related to the ...
[28]
[PDF] The ecology of congeneric resprouters and reseeders (Hypericum ...
Chapter 2 examines fire responses of Hypericum species after fire and clipping. Life histories of species were defined on the basis of this study as ...
[29]
Induction of hypericins and hyperforins in Hypericum perforatum in ...
Plants respond to herbivore and pathogen attack by a variety of direct and indirect mechanisms that include the induction of secondary metabolites.
[30]
Hypericin and pseudohypericin concentrations of a valuable ... - NIH
Hypericin and pseudohypericin concentrations of a valuable medicinal plant Hypericum perforatum L. are enhanced by arbuscular mycorrhizal fungi - PMC.
[31]
Hypericum perforatum (St John's wort) | CABI Compendium
Jun 22, 2015 · Phylum: Spermatophyta. Subphylum: Angiospermae. Class: Dicotyledonae. Order: Theales. Family: Clusiaceae. Genus: Hypericum. Species: Hypericum ...<|separator|>
[32]
Habitat preference and vulnerability to drought of three Hypericum ...
Hypericum species from moist habitats could decline if longer drought episodes become more common in the future. KEYWORDS: Andes · Colombia · drone photography ...
[33]
Hypericum perforatum - an overview | ScienceDirect Topics
The genus Hypericum L. (Hypericaceae) contains 484 species that have been classified into 36 taxonomic sections in all the continents except Antarctica (Bejaoui ...
[34]
St. John's wort (Hypericum perforatum) - UIC Heritage Garden
The Greek physicians of the first century, Galen, Dioscorides, Pliny, and Hippocrates, recommended SJW as a diuretic, wound-healing herb, treatment for ...
[35]
Medical Attributes of St. John's Wort (Hypericum perforatum) - NCBI
perforatum consist of freely branching shrubby herbs that typically range from 40 to 80 cm in height (Muenscher 1946; Gleason and Cronquist 1991). The stems and ...<|control11|><|separator|>
[36]
Hyperforin: Uses, Interactions, Mechanism of Action | DrugBank Online
Jun 13, 2005 · Hyperforin is believed to be the primary active constituent responsible for the antidepressant and anxiolytic properties of the extracts of St. John's wort.
[37]
Antidepressant-like activity of adhyperforin, a novel constituent of ...
Jul 9, 2014 · It was well documented that hyperforin inhibited the synaptic uptake of serotonin (5-HT), norepinephrine (NE) and dopamine (DA) and hyperforin ...
[38]
Clinical use of Hypericum perforatum (St John's wort) in depression
Mar 1, 2017 · For patients with mild-to-moderate depression, St John's wort has comparable efficacy and safety when compared to SSRIs.
[39]
Efficacy of St. John's Wort Extract WS 5570 in Major Depression
H. perforatum extract WS 5570 was found to be safe and more effective than placebo for the treatment of mild to moderate depression.
[40]
St John's Wort for Depression: A Systematic Review - JAMA Network
Jan 24, 2000 · St John's wort is more effective than placebo in the treatment of mild to moderate depression. The absolute increased response rate with the use of St John's ...
[41]
[PDF] final-european-union-herbal-monograph-hypericum-perforatum-l ...
Nov 23, 2022 · Traditional herbal medicinal product for the supportive treatment of nervous restlessness and associated with difficulties in falling asleep. ...Missing: approval | Show results with:approval
[42]
Topical application of St. John's wort (Hypericum perforatum)
Topical St. John's wort preparations such as oils or tinctures are used for the treatment of minor wounds and burns, sunburns, abrasions, bruises, contusions, ...
[43]
Hypericum perforatum: Traditional uses, clinical trials, and drug ...
Hypericum perforatum, or St. John's wort, is used traditionally for wound healing, mild depression, and other conditions, and as an anti-depressant.
[44]
St. John's wort - Mayo Clinic
Mar 21, 2025 · St. John's wort can treat mild to moderate depression. But the supplement interacts with many medicines and can cause serious side effects.
[45]
St John's wort (Hypericum perforatum): drug interactions and clinical ...
The most commonly reported adverse reactions for SJW are gastrointestinal symptoms, allergic reactions, dizziness/confusion, tiredness/sedation and dry mouth.
[46]
Effect of St John's Wort on Drug Metabolism by Induction of ...
Sep 17, 2003 · A 14-day course of St John's wort administration significantly induced the activity of CYP 3A4 as measured by changes in alprazolam pharmacokinetics.
[47]
https://jamanetwork.com/journals/jama/fullarticle/197306
[48]
St. John'S Wort - Uses, Side Effects, and More - WebMD
St. John's wort is a plant native to Europe with yellow, star-shaped flowers. It's often used for depression but can cause serious interactions with some drugs.
[49]
Mania associated with St. John's wort - ScienceDirect.com
Dec 15, 1999 · St. John's wort may precipitate hypomania, mania, or an increased cycling of mood states, particularly in patients with occult bipolar disorder.
[50]
Hypericum calycinum St. John's wort from North Creek Nurseries
Hardiness Zone: 5-7 ; Height: 15-18 Inches ; Spread: 24 Inches ; Spacing: 12 Inches ; Bloom Color: Yellow.
[51]
Hypericum olympicum | BBC Gardeners World Magazine
It's ideal for growing at the front of a sunny border or ina rock garden. Plants self-seed readily. Explore other varieties of hypericum to grow: Hypericum ' ...
[52]
https://www.gardenersworld.com/plants/hypericum-olympicum/
[53]
Hypericum Plant Growing & Care Guide for Gardeners
Nov 25, 2023 · Learn About Growing Hypericum Plants, such as Aaron's Beard, St John's Wort, and Rose of Sharon. Gardener's HQ Plant Guides.
[54]
How to Grow St John's Wort | BBC Gardeners World Magazine
Jun 16, 2022 · All you need to know about growing St John's wort (Hypericum) in our Grow Guide. Expert growing advice from BBC Gardeners' World Magazine.
[55]
Hypericum Archives - Gardenia.net
Hypericum, commonly known as St. John's Wort, is a genus of flowering plants in the family Hypericaceae, comprising around 490 species.
[56]
Managing Pests in Gardens: Trees and Shrubs: Hypericum—UC IPM
Provide moderate to regular amounts of water. They do best in mild, moist areas. Reduce disease development by avoiding overhead watering in the evening. Flower ...
[57]
https://ipm.ucanr.edu/PMG/GARDEN/PLANTS/hypericum.html
[58]
St John's wort | Meat & Livestock Australia - MLA
St John's wort is a weed that can cause photosensitization in livestock, leading to low productivity and sometimes death. Poisoning is more common in spring ...
[59]
St. John's Wort: Ancient Herbal Protector - Christopher Hobbs
Dioscorides, the foremost herbalist of the ancient Greeks, mentions four species of Hypericum—Uperikon, Askuron and Androsaimon, andkKoris–which he recommends ...
[60]
St John's wort beetles more than pay off: A cost benefit analysis
The St John's wort biocontrol programme ran from 1943–1992 and cost NZ$0.28 million (2022 value). During this time three biocontrol agents were released: two ...Missing: aspects | Show results with:aspects
[61]
(PDF) Paleobiology of the genus Hypericum (Hypericaceae)
Fossil seeds of Hypericum miocenicum Dorof. emend. Mai are recorded from the Late Oligocene (28.4-23 Ma) of. Saxonia and Lusatia (Germany), but also from ...Missing: Baltic amber
[62]
The Case of Hypericum (Hypericaceae) - PMC - PubMed Central - NIH
These studies, however, have relied on using fossils as additional lineages in the phylogeny, which requires coding the morphological traits of the fossil taxa ...
[63]
Map showing the approximate distribution of the most relevant fossil...
For example, the lack of fossil record of Hypericum in North America is surprising since several species of Hypericum are endemic to this region. Despite ...
[64]
a survey of the fossil record and its palaeogeographic implications
Jun 30, 2012 · Here, we survey the fossil record of Hypericum from the literature, with special emphasis on the oldest fossil remain, Hypericum antiquum, from ...
[65]
Oligocene niche shift, Miocene diversification – cold tolerance and ...
May 6, 2015 · That is, the adaptation of Hypericum to colder climates first evolved during the Oligocene but diversification rates increased c. 13–17 million ...
[66]
Integrating Fossils, Phylogenies, and Niche Models into ...
The ancient origin of Hypericum, global geographic distribution and high levels of species diversity constitute a new challenge for fossil-modeling ENM studies ...Missing: Laurasian | Show results with:Laurasian
[67]
Species Profile for Highlands scrub hypericum(Hypericum cumulicola)
Highlands scrub hypericum (Hypericum cumulicola) · Taxonomy: · Listing Status: Endangered · Where Listed: WHEREVER FOUND · General Information · » Range Information ...
[68]
[PDF] Highlands Scrub Hypericum 5-Year Review - Amazon AWS
Mar 15, 2021 · Highlands scrub hypericum is listed as endangered by the State of Florida on the Regulated Plant Index (Florida Department of Agriculture and ...
[69]
Challenges Towards Hypericum Sinaicum Conservation in South ...
Aug 6, 2025 · Results found that drought, feral donkeys and over collection are the most harmful threats for Hypericum sinaicum in Saint Katherine ...
[70]
(PDF) The impact of climate change on Hypericum elodes L ...
Aug 6, 2015 · The impact of climate change on Hypericum elodes L. (Hypericaceae) ... threats of climate change is one of the strategic measures to ...
[71]
Creeping St. John's-wort (Hypericum adpressum)
Conservation Actions In 2023, Missouri Botanical Garden seed bank staff performed a 5-year viability check on the Hypericum adpressum in ...Missing: measures | Show results with:measures