| Hypericum grandifolium | |
|---|---|
 | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Malpighiales |
| Family: | Hypericaceae |
| Genus: | Hypericum |
| Section: | Hypericumsect. Androsaemum |
| Species: | H. grandifolium |
| Binomial name | |
| Hypericum grandifolium | |
Hypericum grandifolium, thelarge-leaved St John's wort, is a species offlowering plant in the familyHypericaceae. The plant is a bushyshrub that can grow to almost 2 meters tall. It has large leaves, golden yellowpetals, andseed capsules that split open.H. grandifolium is native to theCanary Islands andMadeira inMacaronesia, but has becomeinvasive in other regions, includingCalifornia, after escaping from cultivation as anornamental plant. It isparasitized bywasps andfungi, and is capable of reproducing through itsrhizomes.
First described in 1821 byJacques Choisy, the ambiguity of its original description meant that the species was often misidentified. Specimens were variously calledH. elatum,H. anglicum,Androsaemum webbianum, and others. The species was placed into sectionAndrosaemum ofHypericum byNorman Robson in 1984, and it is most closely related in appearance and classification to the other species in the section, especiallyH. androsaemum,H. hircinum, andH. × inodorum. The species is not used in modern medical applications, but may haveanticancer potential and could be used to treat earedemas.
Thegenus nameHypericum is possibly derived from theGreek wordshyper (above) andeikon (picture), in reference to the tradition of hanging the plant over religiousicons in the home.[1] Thespecific epithetgrandifolium is made of the Latin wordsgrandis (large, full) andfolium (leaf).[2] As such, it is called the large-leaved St John's wort in English.[3]Hypericum grandifolium is known asmalfurada,[note 1][4]malfurada grande, andcorazoncillo in Spanish, the language used where it is native.[5][6] The namecorazoncillo is adiminutive form of the Spanish word for heart,corazon.[7][8]
Hypericum grandifolium is a bushy shrub that grows 50–180 centimeters tall. Its branches generally grow upright or almost upright.[9] Across its distribution, different populations look almost identical and the species has minimal geographic variation in appearance.[10]
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When the plant is young, thestems are somewhat flattened and have four lines that run longitudinally up their length. When it matures, they become more cylindrical and have only two lines. There arenodes with leaves every 0.2–0.4 cm along the stem. The bark on the outside of the stem is scaly.[9]
The leaf blades are directly connected to the stem, and sometimes partially wrap around it. The blade is roughly 4–9 cm long by 2.5–4.5 cm wide and is a triangular-oval or oblong-oval shape. The end is blunt or rounded, and the base is flat or rounded. It is the same color on top and bottom and has a papery texture. There are four or five pairs of large lateral veins, and the leaf's network of tiny tertiary veins is visible on the top side. The leaf'sglands are small, but they are found densely along its edges.[9]
Eachcluster of flowers has anywhere from 1–13 individual flowers. They come from two nodes on the stem that are separated by the same distance as the leaves are from each other. The flower cluster is shaped like a wide pyramid or closer to acorymb, with the stems spreading out broadly. Sometimes there will be accessory flowers lower on the branches that carry the main clusters. Each flower is carried by apedicel that is 0.5–1.1 cm long. The leaf-likebracts may be the same size as other leaves, or could be smaller. They are elongated and may taper to a point.[11]
Each flower is 3–4.5 cm wide. Before blossoming, the buds are an imperfect globe shape with an end that is blunt or rounded. Thesepals overlap one another and vary in size. They become larger during flowering and persist while the plant is fruiting. There are glands on the sepals in linear patterns and individual points; the glands are denser along the edges. The petals are golden yellow, measuring 1.8–2.2 cm long and 0.6–0.8 cm wide. Thestamens are grouped together in bundles of around 30–40, with the longest in the bundle being around 1.5–2.0 cm long. Thestyles grow upright and are slender, with a narrowstigma that ends in a distinct head. Theseed capsule is 0.8–1.3 cm long with a leathery texture and a pointed end. After the plant fruits, the seed capsule entirely splits. The seeds inside are yellow-brown and around 0.12 cm long, with a wing-like growth on one side and none on the ends.[11]
Hypericum grandifolium differs from both H. androsaemum and H. hircinum by its bigger overall size and larger leaves. It also differs from H. androsaemum by having dry fruit (as opposed to a soft and fleshy berry), and fromH. hircinum by having sepals that do not fall off.[12] It has at times been confused withHypericum × inodorum by some botanists,[10] which is an intermediate form of H. androsaemum andH. hircinum.[13]
Hypericum grandifolium produces severalsecondary metabolites in detectable quantities.Hyperoside andquercitrin are found in major concentrations;chlorogenic acid,isoquercitrin, andquercetin are present in smaller concentrations.[14] The species also has a diverseessential oil profile.Nonane and variouscaryophyllenes are by far the most prolific oils,[15] but there is a wide array of compounds in more minute concentrations. These are mostlyalkanes andsesquiterpenehydrocarbons.[16]
Hypericum grandifolium was first formallydescribed byJacques Denys Choisy in 1821.[17] He collected the species'type specimen on the island ofTenerife.[9] This description was one of the first that dealt withMacaronesian flora spanning multiple island groups.[18] In it, Choisy gave H. grandifolium the following brief identifying description:[19][note 2]
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| Cladogram showing thephylogeny and relationships ofH. grandifolium within the "Androsaemum-group" based on Meseguer et al. 2013[20] |
Confusion around the identity and properties ofHypericum grandifolium was present throughout the 19th century. Cultivated specimens in Britain were variously called H. elatum (today H. × inodorum), H. anglicum, andAndrosaemum webbianum.[21] Choisy's original description was somewhat ambiguous, and could apply toH. × inodorum as well.[22] As such, H. grandifolium was at times considered asynonym of that species.[23] The last name arose because the species was sometimes placed into the defunct genusAndrosaemum. This placement was refuted byWilliam Hooker in 1844, who synonymized the nameA. webbianum with H. grandifolium. His reasoning was that the species did not share certain characteristics with the rest of the genusAndrosaemum as it was at that time (such as their berry-like fruit).[24] The species was included inNorman Robson'smonograph of the genusHypericum in 1984, and he placed it into the newly arrangedsectionAdenosepalum and allied it most closely with H. foliosum.[9] A 2013 study usedBayesian inference to establish thephylogeny and close relations ofHypericum species. SectionAndrosaemum, includingHypericum grandifolium, was placed into anOld World taxon called the "Androsaemum-group" with several other sections. The study also determined that H. grandifolium was most closely related toHypericum hircinum andHypericum foliosum.[20]
The native distribution ofHypericum grandifolium are the SpanishCanary Islands and the Portuguese island ofMadeira. The species is also a garden plant, and has becomeinvasive after escaping fromcultivation in non-native areas. For example, it is invasive and spreading in theSan Francisco Bay Area, forming densestands that force out native plants.[3] It was first recorded in California in 2010, and is suspected to be harmful to the native ecology by theCalifornia Invasive Plant Council.[5] H. grandifolium has becomenaturalized in parts of Australia and in Chile,[3] but is listed as a weed in other parts of Australia likeSouth Australia andVictoria.[5]
The species can be found at elevations of 200–1,500 meters on the Canary Islands and 400–500 on Madeira. Its habitat is among evergreen forests like those ofLaurus trees. It is also present on stony hillsides and cliffsides.[11] In areas that have been deforested bywildfire,Hypericum grandifolium is a colonizing species that grows in the years following the disturbance.[25] It often grows alongside the shrubAgeratina adenophora in California, where both species are invasive.[5]
Hypericum grandifolium is a host to severalparasites. These include thewaspEuderomphale gomer, therust fungusMelampsora hypericorum,[26] and rarely the honey fungusArmillaria.[27]H. grandifolium is capable of reproducing through itsrhizomes, and can also form thickets from itsrootstock.[3] It is possible topropagate H. grandifolium form either softwood or semi-ripecuttings.[27]
Themethanol-water extracts ofHypericum grandifolium exhibit moderatein vitroanticancer potential against human tumor cells that was demonstrated in laboratory testing, and amongHypericum species native to the Canary IslandsH. grandifolium is the most effective in this regard. The plant's extracts were particularly effective at inducingcell death ofHeLa cervical cancer.[28][29] When compared toHypericum canariense andHypericum reflexum, the species showed the least amount ofantioxidant andantimicrobial activity. It had no impact ongram-negative bacteria and only minimal impact ongram-positive bacteria.[30] However, its essential oil extracts have demonstrated effectiveness in reducing ear and pawedemas.[31] A review of the medicinal properties of variousHypericum species in 2015 stated that the species was one of several that was effective againstdrug-resistant bacteria, especiallyEnterococcus faecalis.[32] In laboratory mice, the plant inducedantidepressant-like effects, likely a result of its flavonoids and benzophenones,[33][34] and has also demonstrated properties that restrictnociception, which could reduce pain.[35]