The poison is called Tremetol and is found in this species and a few species of goldenrod. It will kill calves and other animals, but didn't necessarily affect adult cows. It has a number of terrible symptoms including vomiting, trembling, abdominal pain, delirium, coma, and finally death. It was a huge problem for the early settlers because no one could figure out the cause.
Finally, a frontier doctor named Anna Pierce Hobbs Bixby learned the cause of it from a Shawnee medicine woman. However it wasn't until 55 years after her death that researchers confirmed and published her discovery. At the time, the medical profession didn't take women or Native Americans seriously and so they suffered many years of milk sickness before they finally solved the problem.
It is still possible to get it today if you obtain milk from a free range cow that has access to White Snakeroot. If you get your milk from a local farmer, be sure that the cows aren't grazing in the woods.
|The plants are typically found in rich woods|
|Opposite leaves on long stems|
|Leaf is somewhat heart shaped at the base and pointy on the end|