Guttiferae - St. Johnís-wort family

Gerald A. Mulligan
Research Scientist and Research Institute Director (retired) and presently Honorary Research Associate, Agriculture and Agri-Food Canada,
Ottawa, Ontario K1A 0C6, Canada

Awarded the George Lawson Medal by the Canadian Botanical Association in 2006.
Awarded the Faculty of Macdonald, McGill University, Most Distinguished Alumni Award on October 18, 2014.
Read his biography "The Real Weed Man" available in print and ebook.

Hypericum perforatum L., St.John's-wort, millepertuis commun
Perennial, spreading by seeds, and by shoots from underground runners; apomictic; flowering stems 1 to 3 feet (1 to 9 dm.) high; yellow flowers with black dots around the edges; mostly absent from the mid-west, but common elsewhere; pastures, meadows, roadsides, and waste places; introduced from Europe. Grazing by livestock can cause photosensitization, resulting in sickness or even death.

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Weed Name Photo Weed Name Photo
St.John's-wort, millepertuis commun St.John's-wort, millepertuis commun
(winter)
St.John's-wort, millepertuis commun
(shoots from underground runners)
St.John's-wort, millepertuis commun
(seedling)
St.John's-wort, millepertuis commun (NC) St.John's-wort, millepertuis commun (plants)
St.John's-wort, millepertuis commun
(F&M)
     
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