Hypericum
A genus of flowering plants with worldwide distribution and medicinal glands.
Hypericum is a genus of flowering plants in the family Hypericaceae, with a nearly worldwide distribution absent only from deserts and polar regions. The genus is notable for its taxonomic monograph by Norman Robson, who recognized 36 sections within Hypericum, and for its species' production of naphthodianthrones and phloroglucinol derivatives, which give rise to characteristic glandular patterns and medicinal properties.
- distribution
- nearly worldwide, missing from deserts and polar regions
Lore & Background
Hypericum species vary widely in habit, including trees, shrubs, annuals, and perennials. The genus is characterized by two types of glands: dark glands containing naphthodianthrones (hypericin or pseudohypericin) that produce a red stain when crushed, and pale glands that secrete oils and phloroglucinol derivatives like hyperforin.
Reader's Guide
Hypericum is significant for its widespread use in traditional medicine, particularly St. John's wort (Hypericum perforatum), and for its ecological role as both a noxious weed and a host for specialized insects. The genus has been the subject of a comprehensive taxonomic monograph by Norman Robson, who divided it into 36 sections. Many species are invasive in temperate zones, and biocontrol agents such as Chrysolina beetles and the St. John's-wort root borer have been employed against them. The genus also serves as the sole food plant for the treble-bar moth caterpillar and hosts larvae of several other Lepidoptera species. Its chemical compounds, especially hypericin and hyperforin, have been studied for their biological effects, though the article does not specify medical uses.
Did You Know?
- The name 'Hypericum' derives from the Greek word for the plant, possibly meaning 'above pictures' due to its use over shrines to repel evil spirits.
- Paracelsus called the red secretions from crushed dark glands 'Johannes-blut' in the 16th century, linking the plant to St. John and giving rise to the common name St. John's wort.
- Some Hypericum species, such as H. lloydii, have seedlings susceptible to fungal infection in moist conditions, but H. chapmanii is a terrestrial shrub, not an aquatic plant.
- The genus includes species with white or pink petals, such as Hypericum albiflorum var. albiflorum and H. geminiflorum, though most have yellow petals.
Frequently Asked Questions
What is Hypericum?
Hypericum is a diverse genus of flowering plants in the Hypericaceae family, best known to many herbalists by the common name St. John's wort. It is one of the more widespread and chemically interesting genera you will encounter in any botanical reference.
Where do Hypericum species grow?
These plants are found on nearly every continent, adapting to a broad range of temperate and subtropical habitats. The only regions where they are naturally absent are true desert zones and the polar areas.
What chemicals make Hypericum medicinally notable?
The genus produces two signature compound families—naphthodianthrones and phloroglucinol derivatives—that underpin its long history of therapeutic use. These same molecules are responsible for the distinctive glandular markings on the leaves and stems that help identify the plants.
Who is the key taxonomist behind modern Hypericum classification?
Botanist Norman Robson is widely regarded as the definitive authority on this genus. His landmark monograph organized Hypericum into 36 distinct sections, and his framework still anchors most contemporary classifications.
Why is Hypericum a must-know entry for herb and spice fans?
Its near-global distribution, chemically rich glandular tissues, and centuries-old medicinal reputation make it a standout in any herbalist's collection. Few other genera combine such broad geographic reach with such a well-documented pharmacological profile.
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