St. John's Wort (Hypericum perforatum L.) also known as: Common St. John's Wort, Klamathweed and Klamath Weed Division - Magnoliaphyta Class - Magnoliopsida Subclass - Dilleniidae Order - Theales Family - Clusiaceae Genus - Hypericum Weeds Taxonomic List List by Scientific Name List by Common Name