Page authors: Don Knoke, David Giblin
Hypericum tetrapterum
square-stalked St. John's wort

Distribution: Occurring west of the Cascades crest in Washington; southwestern British Columbia to southwestern Washington.

Habitat: Freshwater intertidal marshes, floating logs, and damp gravel.

Flowers: July-September

Origin: Introduced from Europe

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Bumblebees, bees, flies, wasps


Perennial, the stems 4-winged, erect, 4-10 dm. tall.


Leaves opposite, sessile, somewhat clasping, ovate-lanceolate to oblong-ovate, with translucent dots.


Inflorescence of leafy-bracteate cymes; sepals 5, pointed, not black-dotted; petals 5, pale yellow; flowers about 10 mm. wide; stamens numerous, styles 3.


Capsule 3-celled.

Accepted Name:
Hypericum tetrapterum Fr.
Publication: Novitiae Florae Suecicae 236. 1814.

Synonyms & Misapplications:
(none provided)
Additional Resources:

PNW Herbaria: Specimen records of Hypericum tetrapterum in the Consortium of Pacific Northwest Herbaria database

WA Flora Checklist: Hypericum tetrapterum checklist entry

OregonFlora: Hypericum tetrapterum information

E-Flora BC: Hypericum tetrapterum atlas page

CalPhotos: Hypericum tetrapterum photos

12 photographs:
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