Triadenum Rafinesque. Marsh St. John's-wort.
A genus of about 10 species, perennial herbs, of e. North America and e. Asia. Sometimes merged into Hypericum, Triadenum is one of a few basal clades that seem better separated as separate at generic rank from Hypericum.
Ref: Robson (2015d) In Flora of North America Editorial Committee (2015). Show full citations.
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