Northern Prairie Wildlife Research Center
Northeast Wetland Flora
Field Office Guide to Plant Species
Slender St. John's-wort
Hypericum mutilum L.
- Family: St. John's-wort (Guttiferae)
- Flowering: July-September
- Field Marks: This species is distinguished by its ovate, oblong, partly clasping leaves with
3-5 nerves and its short-ellipsoid capsules.
- Habitat: Wet ground.
- Habit: Perennial herb with fibrous roots.
- Stems: Upright, slender, much branched, smooth, up to 2 feet tall.
- Leaves: Opposite, simple, ovate-oblong, rounded at the tip, rounded or sometimes clasping at the base, smooth, without teeth, 3- to 5-nerved, up to 1 3/4 inches long, up to 3/4 inch wide.
- Flowers: Several in cymes, each flower yellow, about 1/6 inch across, subtended by linear bracts.
- Sepals: 5, green, free from each other, lanceolate, sharp-pointed at the tip, up to 1/6 inch long.
- Petals: 5, yellow, free from each other, oblong, rounded at the tip, 1/6-1/4 inch long.
- Stamens: 5-10.
- Pistils: Ovary superior, smooth.
- Fruits: Capsules narrowly ellipsoid, smooth, rounded at the tip, 1/8-1/6 inch long, with persistent styles.
- Notes: Gleason and Cronquist use the name Clusiaceae for this family.
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