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Blue Ridge St. Johnswort (Hypericum ×mitchellianum Rydb.)

Also classified as Hypericum mitchellianum Rydb.

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LegendColor
Native
Native or Not Present
Native or Expanded
Expanded or Not Present

This map is based on our research. We have checked its accuracy to Level 3 ecoregions. Although this plant occurs somewhere in each of these regions, it may only occur in a small part of some or all of them.

BONAP reports this species as adventive in one county of Maryland, but the Maryland Plant Atlas does not. We marked this portion of its range as possibly expanded, rather than possibly introduced, due to the proximity to the native range.

This species is widely suspected, but not unambigously confirmed, to be a hybrid of mountain st. johnswort (Hypericum graveolens) and spotted st. johnswort (Hypericum punctatum). Evidence supporting this hypothesis include intermediate morphology and reproductive patterns, and a distribution nearly completely contained within that of H. graveolens. This species has also been recorded hybridizing with H. graveolens in the wild, which, if it itself is a hybrid, would be an example of backcrossing and could make it likely that there is gene flow from H. punctatum to H. graveolens, which could be relevant because that species is rare and has a limited range and its populations are thus of conservation concern.

The two putative parent species have also been artificially crossed, and produce vigorous offspring. The current status of thought on this species' hybrid status is reflected in there being many sources referring to it as a hybrid, but also many referring to it as a proper species in its own right.

• Hypericum mitchellianum (Blue Ridge St. Johnswort) | USDA PLANTS Database (About This Site)

• Blue Ridge St. John's Wort | iNaturalist (About This Site)

• Hypericum mitchellianum | Biota of North America Project (BONAP) (About This Site)

• Hypericum × mitchellianum Rydb. | Plants of the World Online (POWO) (About This Site)

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