Northern Prairie Wildlife Research Center
Northeast Wetland Flora
Field Office Guide to Plant Species
Coppery St. John's-wort
Hypericum denticulatum Walter
- Family: St. John's-wort (Guttiferae)
- Flowering: June-September
- Field Marks: This herb differs by having more than 20 stamens, 3 styles free to the base,
and smooth leaves and stems.
- Habitat: Moist woods, swamps, wet ditches, pine barrens.
- Habit: Perennial herb with fibrous roots.
- Stems: Upright, branched or unbranched, smooth, 4-angled, up to nearly 2 feet tall.
- Leaves: Opposite, simple, spreading to ascending, elliptic to narrowly ovate, rounded or pointed at the tip, rounded or tapering to the sessile base, smooth, sometimes dotted, up to 1 inch long, up to 3/4 inch wide.
- Flowers: Few to several in racemes, the racemes on strongly ascending stalks, the flowers yellow, about 1/2 inch across, subtended by small, linear bracts.
- Sepals: 5, green, narrowly ovate, pointed at the tip, up to 1/3 inch long, smooth.
- Petals: 5, copper-yellow, free from each other, up to 1/2 inch long.
- Stamens: Numerous.
- Pistils: Ovary superior; styles 3, free from each other.
- Fruits: Capsules ovoid, smooth, up to 1/4 inch long, with numerous black seeds.
- Notes: Gleason and Cronquist use the name Clusiaceae for this family.
Previous Species -- Canadian St. John's-wort (Hypericum canadense)
Return to Species List -- Group 7
Next Species -- Slender St. John's-wort (Hypericum mutilum)