Asclepiadaceae - milkweed family
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.
Asclepias syriaca L., common milkweed, asclépiade commune
Perennial with a white, sticky juice, spreading by seeds and by thick fleshy roots; allogamous; 2 to 4 feet (6 to 12 dm.) high; flowers usually purplish; pastures, grain fields, cultivated fields, roadsides, fencerows, and waste places in settled areas of the eastern half of North America. A common food plant for the larvae of the monarch butterfly. Some poisoning and death of sheep and cattle has been reported. However, livestock usually avoid eating this plant.
Cynanchum louiseae Kartesz & Gandhi (= Vincetoxicum nigrum (L.) Moench), black dog-strangling vine, dompte-venin noir
Perennial, spreading by seeds; twinning stems 3 to 12 feet (10 to 40 dm) high; flowers dark purple or blackish; southern Quebec and Ontario; in gardens, hedgerows, fencerows, old fields, thickets, open forests and disturbed areas; introduced from western Europe. Probably toxic to livestock and humans.
Text and photos of black dog-strangling vine by Stephen J. Darbyshire
Cynanchum rossicum (Kleopow) Borhidi (= Vincetoxicum rossicum (Kleopow) Barbar), dog-strangling vine, dompte-venin de Russie
Perennial, spreading by seeds; twinning stems 3 to 9 feet (10 to 30 dm) high; flowers pinkish, maroon, reddish brown or very rarely white; southern Quebec and Ontario; in gardens, hedgerows, fencerows, old fields, thickets, open forests and disturbed areas; introduced from eastern Europe. Toxic to livestock and probably humans.
Text and photos of dog-strangling vine by Stephen J. Darbyshire
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