BugwoodWiki Article

common St. Johnswort
Hypericum perforatum L.

Overview

Appearance
Hypericum perforatum is a perennial, rhizomatous herb that can reach 4 ft. (1.2 m) in height.
Foliage
Leaves are opposite, sessile, elliptic, 0.4-1.2 in. (1-3 cm) long and dotted with many pellucid glands.
Flowers
Flowering occurs from June to September, when bright yellow flowers develop at the tips of the stems. Flowers have five petals and many stamens. Petals typically have black glands along the margins.
Fruit
The fruits are three-chambered capsules with three persistent styles.
Ecological Threat
Hypericum perforatum has been used to treat mild depression, but has been shown to cause hyper photosensitivity. Plants inhabit rangelands, pastures, roadsides and forest clearings. St Johnswort is native to Europe. Hypericum perforatum may be poisonous to cattle in large doses.

Resources

Image Sets
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Maps


EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org

EDDMapS Distribution

State Invasive List - This map identifies those states that list this species on their invasive species list. For more information, visit Invasive.org

State Invasives List

Taxonomic Rank

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Subclass: Dilleniidae
Order: Theales
Family: Clusiaceae
Genus: Hypericum

Other System Links

Plants: HYPE
Bayer: HYPPE
GRIN: 19600
ITIS: 21454
NPDN Pest: PCBABBA
NPDN Host: 36404

Synonyms and Other Names

Other Common Names:
Klamathweed, St. John's wort

Categories

Category: Forbs/Herbs