Prickly Lettuce (Lactuca scariola), also known as milk thistle or compass plant, is a commonly found in fields, roadsides and waste places. A native to Eurasia, it has become naturalized throughout the world.
The name "Lactuca" refers to the milky white juice that is produced by the plant. It is called the compass plant as the bottom leaves tend to point north and south.
It is the closest wild relative of domesticated lettuce (Lactuca sativa).
