Common St. Johnswort
August 25, 2015
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EmailHypericum perforatum L.
Life cycle
Multi-stemmed, shrub-like perennial.
Young common St. Johnswort plant.
Leaves
Opposite, narrow oval to oblong leaves have round to pointed tips and entire margins, and attach directly to the stem. Leaves are covered with small, transparent dots when viewed against the light.
Transparent dots on common St. Johnswort leaf.
Stems
Erect with numerous branches and up to 3 feet tall. Herbaceous stems are often reddish in color and become woody at the base with maturity.
Flowers and fruit
Bright yellow to orange-yellow flowers with five petals are approximately 0.75 inch wide, often with several black dots along the petal margins. Fruit are capsules with three cells containing numerous dark brown to black, cylinder-shaped seeds.
Common St. Johnwort flowers (left). Black dots along the petal margin of common St. Johnswort (right).
Reproduction
Seeds and short runners.
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