White Snakeroot (Eupatorium rugosum)

This plant was found on a walk in Robert E Lee park.  Did not seem common but apparently toxic to goats and cattle, then toxic even fatal to humans who eat the meat or drink the milk of the animals.  Said to be a common cause of death for settlers moving westward who were not familiar with the plant.  There are stories online about heroic efforts of pioneer doctors to diagnosis the milk sickness.  Said to cause the death of Abraham Lincoln's mother.

It has similar small white flowers as boneset but a much longer leaf stem or petiole. Three prominent veins are seen on the upper leaf surface. The disease is rare now that pastures are more controlled, and milk from any one cow is diluted. There did not seem to be any mention of deer eating the plant in the fall and thus becoming toxic. Symptoms are shaking,staggering, vomiting, intestinal pain.  In the twentieth century the toxin was identified as tremetol.

The picture shows the leaf with the marks from a leaf miner, and the flowers with a couple of reasons to take the photos outdoors.  Finally there is the plant in its natural setting.

The last photo was almost one month later.  Is this the late stage flower of the white snakeroot? There are discussions on the net about misdiagnosing boneset, in fact this plant is sometimes called tall boneset. But the leaf shape seems consistent with white snakeroot.   There are few stock images as the plant goes to seed,so some uncertainty.

More detail on the leaf miner, many varieties, gets bigger,bigger track as larva grows, then molts and flies away at the large end of the trail.