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Japanese St. John's wort (Hypericum japonicum)


Hypericum japonicum, also known as matted St. John's-wort or Japanese St. John's wort, is an annual herb in Hypericum sect. Trigynobrathys. H. japonicum is unusually small for a St. John's wort, growing only 2–5 cm (0.79–1.97 in) tall. Its stems are green and 4-angled, with 2–52 mm (0.079–2.047 in) long internodes that usually exceed the leaves. The leaves are sessile and spreading and are persistent. The species is 30-flowered with flowers branching from up to three nodes. The flowers are 4–8 mm (0.16–0.31 in) in diameter and their petals are bright yellow or orange. The species' stamens number 5-30 in irregular groups or in five groups when few in number. Its seeds are approximately 50 mm (2.0 in) long. The species flowers primarily from October-March.

Taxonomic tree

  • Domain: Eukarya

    • Kingdom: Plantae

      • Phylum:

        • Class: Magnoliopsida

          • Order: Malpighiales

            • Family: Hypericaceae

              • Genus: Hypericum