Hypericum pyramidatum (Great St. Johnswort)
|Also known as:||Giant St. John's-wort|
|Family:||Hypericaceae (St. John's-wort)|
|Habitat:||sun; moist; along shores, wet meadows, thickets|
|Bloom season:||July - August|
|Plant height:||2 to 5 feet|
|Wetland Indicator Status:||none|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Flowers are from 2 to 2½ inches across with 5 bright to golden yellow petals and many long yellow stamens with orange tips. In the center is a green pyramid shaped ovary with 4 or 5 red-tipped styles that are fused at the base. A flowers is at the end of a stem that arises from a leaf axil in the upper part of the plant.
Leaves and stem:
Leaves are up to 3 inches long and 1 inch wide, toothless and hairless, rounded at the base and slightly tapering to a point at the tip, with no leaf stem. There are glandular dots or streaks scattered on the surface. Attachment is opposite. The main stem is 4-angled on young plants, becoming 4-lined with maturity.
While the general shape of this flower resembles other St. John's-wort species, the size of the flower sets it apart from the rest. Great St. John's-wort also goes by Latin name Hypericum ascyron, but the accepted name in Minnesota is Hypericum pyramidatum. All Hypericum species have switched from the Clusiaceae family to Hypericaceae.
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Photos by K. Chayka taken at Wild River State Park, Chisago County. Photos courtesy Peter M. Dziuk taken in a private garden in Anoka County (it did not persist well there)
Have you seen this plant in Minnesota, or have any other comments about it?