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Common St. John's Wort
Hypericum erectum
オトギリソウ
A perennial herb of mountain meadows and forest edges. Yellow flowers bloom in summer. When held up to the light, the leaves reveal translucent oil glands and dark spots. Long known as a medicinal plant, the Japanese name 'Otogirisou' (brother-slaying herb) derives from a tragic legend.
Identification Points
- ✓Translucent oil glands and black marginal dots visible on leaves (seen when backlit)
- ✓Yellow 5-petaled flowers with conspicuously numerous stamens
- ✓Stems erect with 2 ridges
Habitat
Mountain meadows, forest edges, and roadsides
Season
July–August (flowers)
Morphological TraitsAI-estimated, needs verification
Growth form
Herb
Flower color
Yellow
Flowering season
Summer
Phylogenetic Positionオトギリソウ科 →
Phylogenetic Position
Angiosperms > Eudicots > Core eudicots > Malpighiales > Clusiaceae
Divergence Era
Late Cretaceous to Paleogene (about 80–70 million years ago)
Evolution Notes
The oil glands of Hypericaceae (some classifications place it in Clusiaceae) are essential oil glands that accumulate repellent substances against herbivores—an evolutionary adaptation.
View on evolution timeline →Sources & References
AI-generated, needs verification