common St. John's-wort, Klamath-weed, St. John's-wort
Etymology: Hypericum: ancient Greek name derived from hyper, "above," and eikon, "picture," from old practice of placing flowers above an image in the house to ward off evil spirits at the midsummer festival of Walpurgisnacht, which later became feast of St. John
Plants: erect, perennial, 2'-3' tall forb with many leafy branches; stems with a sharp ridge below the base of the leaves
Leaves: stalkless, small, 1/4" wide
Flowers: yellow, 5-parted, 5/8"-1" wide, stalked, petals with black dots near the edges; inflorescence a many-flowered, rounded to flat, compound, branched cluster (cyme); blooms June-Sept.
Fruits: 3 chambered capsule
Habitat: disturbed sites, fields, roadsides
Hazardous: Careful, this plant is hazardous!
Invasiveness: Invasive - Eradicate!
Conservation Status: Introduced - naturalized; ecologically invasive
WIS DNR-Bureau of Endangered Resources: Detailed information on Wisconsin invasive species including decription, habitats, control methods Invasive And Exotic Species of North America: Descriptions, management issues, warnings, photos, etc. Atlas of the Wisconsin Prairie and Savanna Flora: by T.S. Cochrane & H.H. Iltis: habitat, distribution infomation / flowering and fruiting times USDA Plants Database: Federal Distribution and detailed information including photos USDA Agricultural Research Service (ARS): Images of seeds, fruits, embryos, etc. Dan Tenaglia's The Missouri Flora: Fabulous photographs; detailed descriptions; color and leave arrangement key. David G. Smith's "Delaware Wilflowers": Beautiful photographs; descriptions Illinois Wildflowers: Wonderful photographs; detailed descriptions; color and leaf arrangement key Purple Sage - Ethnobotanical Information: Detailed usage, preparation, and other helpful information Southwest School of Botanical Medicine: Britton & Brown Illustrated Flora - 2nd Edition (1913) "An Illustrated Flora of the Northern United States and Canada"