E-Flora BC: Electronic Atlas of the Flora of British Columbia

Triadenum fraseri (Spach) Gleason
Fraser's St. John's-wort (Fraser's marsh St. Johnswort)
Hypericaceae (Mangosteen family)
(Previously in Clusiaceae)

Introduction to Vascular Plants
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Distribution of Triadenum fraseri
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Species Information

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Perennial herb from a taproot; stems erect, few branched, glabrous, 30-60 cm tall.
Stem leaves oblong to oblong egg-shaped, unstalked, heart-shaped at the base with rounded or notched tips, 3-6 cm long, 2-3 cm wide, glabrous with translucent glands below.
Inflorescence up to 5- to 50-flowered; petals purplish or flesh-coloured, 5-8 mm long; sepals elliptic or oblong, obtuse, 3-5 mm long; stamens in 3 groups of 3 alternating with 3 large, orange glands.
Membranous capsules, 7-12 mm long; seeds dark purplish, about 1 mm long, finely corrugated and pimply in lines.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Wet bogs, marshes and shorelines in the lowland zone; rare in SW BC, known only from the lower Fraser Valley; introduced from E North America.

Source: The Illustrated Flora of British Columbia


The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Synonyms and Alternate Names

Elodea fraseri Spach.
Hypericum virginicum var. fraseri (Spach) Fern.
Triadenum virginicum subsp. fraseri (Spach) J. Gillett
Triadenum virginicum var. fraseri (Spach) Cooperrider

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References