This section is from the book "A Guide To The Poisonous Plants And Weed Seeds Of Canada And The Northern United States", by Robert Boyd Thomson, H. B. Sifton. Also available from Amazon: A guide to the poisonous plants and weed seeds of Canada and the northern United States.
This plant, like Wild Mustard, is harmful only when its seeds are included in ground feeds. The seeds, which contain a pungent oil, are intensely bitter, and unless an animal is very hungry, it will refuse feed containing any appreciable amount of them. One sample of shorts sent in for examination was accompanied by a statement that two neighbours had bought feed from the same lot. Each found all his pigs dead a few hours after the first feeding. An analysis showed a considerable proportion of Wormseed Mustard, there being 1.7% by weight of whole seeds present. This aroused suspicion, and feeding experiments made since by Dr. Hadwen, though not complete, have practically demonstrated the poisonous character of the seed.
Fig. 25. - Seeds of Wormseed Mustard - Erysimum cheiranthob
Five times natural size.
The plant grows in grain fields and waste places throughout the country, but more plentifully east of Lake Superior. It is an erect plant six inches to two feet high, with dark green, lance-shaped, sparsely toothed leaves, and flowers one-fifth of an inch in diameter, in clusters an inch across at the tips of elongating racemes.
The slender seed pods are erect, on spreading stalks. They are one-half to one inch long, and four-angled. The small seeds, one-twenty-fourth of an inch long, are reddish yellow with the scar end darker. Their characteristic bitter taste as well as their microscopic structure afford a good means of identification.
The Plant and Seed