Amy Stewart has written a fascinating book, “Wicked Plants: The Weed That Killed Lincoln's Mother and Other Botanical Atrocities”, covering plants from A-Z used and misused by folks over the years. My personal favorite is a hemlock known in Scotland as “deid men’s oatmeal.” It looks like carrot but is deadly if consumed. Many a mystery writer has used this plant to kill off some obnoxious foe. See e.g., “Death of a Dreamer” or “Five Little Pigs.”
The San Francisco Conservatory is presenting many of these “wicked plants,” in an exhibition described as “mayhem under glass.” Included are such demonic rogues as the strychnine tree, a source of poison used by many a fictional killer as well as real ones.