I forget whether there is any other case parallel with this curious one of the Sonchus...
"More Letters of Charles Darwin" by Charles Darwin
Introduced plants, Sonchus in New Zealand as example of.
"More Letters of Charles Darwin Volume II" by Charles Darwin
The channel had become filled with reeds, and great quantities of enormous milk or sow thistle (Sonchus oleraceous).
"Australia Twice Traversed, The Romance of Exploration" by Ernest Giles
The common sow-thistle (Sonchus oleraceus) grows all over the country up to an elevation of 6000 feet.
"Darwinism (1889)" by Alfred Russel Wallace
The juice of the "milk-thistles" (Sonchus) will cure warts.
"Current Superstitions" by Various