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St. Johnswort, Perforated St. Johnswort, Common St. Johnswort, Klamathweed

Hypericum perforatum L.

Hypericaceae or Clusiaceae (St. Johnswort Family)

▲ young shoots emerging in spring

▲ pre-flowering mature plant

▲▼ mature, flowering plants

▲▼ flowers

▲ flowering stem, leaves

St. Johnswort, Klamath Weed

·         creeping perennial with creeping roots and 1-2’ tall stems, unbranched below, becoming much-branched above as it begins to produce flower buds

·         flowers are somewhat showy, yellow with black-dotted petals

·         leaves are ovate to lanceolate, 1-3” long and about ½ as wide; leaves also have either black dots or clear dots (depending on species)

·         consumption can cause photosensitivity in livestock—where skin can blister as if from severe sunburn in normal conditions; very toxic to sheep

·         in moist to well-drained, sandy or rocky soils; includes both native and non-native species

 

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