Northern Prairie Wildlife Research Center
Northeast Wetland Flora
Field Office Guide to Plant Species
Great St. John's-wort
Hypericum pyramidatum Ait.
- Family: St. John's-wort (Guttiferae)
- Flowering: July-September
- Field Marks: This attractive species is distinguished by its yellow flowers 2-3 inches across,
its numerous stamens, its 5 styles per flower which are united for the lower half, and its
- Habitat: Wet meadows, rich woods.
- Habit: Perennial herb from thickened rootstocks.
- Stems: Upright, branched, angular, smooth, up to 6 feet tall.
- Leaves: Opposite, simple, broadly lanceolate to ovate, rounded or pointed at the tip, rounded at the sessile and sometimes slightly clasping base, dotted, smooth on both surfaces,up to 4 inches long, up to 1 3/4 inches wide.
- Flowers: Few in a terminal cyme, the cyme up to 4 inches across.
- Sepals: 5, green, free from each other, ovate-lanceolate, pointed at the tip, smooth, not dotted, up to 1/2 inch long.
- Petals: 5, yellow, free from each other, up to 1 1/2 inches long.
- Stamens: Numerous, united in groups of 5.
- Pistils: Ovary superior; styles 5, free above, united below.
- Fruits: Capsules ovoid, 5-chambered, beaked, up to 1 1/2 inches long; seeds numerous, black, smooth.
- Notes: This species is often grown as an ornamental. This family is called Clusiaceae by Gleason and Cronquist.
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