I didn’t recognize this plant, but apparently it is Canada wild lettuce (Lactuca canadensis), aka Florida blue lettuce, tall lettuce, or Canada lettuce. Supposedly it is native to eastern and central North America.

Canada wild lettuce, aka Florida blue lettuce

It’s in the daisy family, Asteraceae.

According to Eattheplanet.org, “The young leaves and stems are edible but should be eaten in moderation. Leaves can be eaten raw in a salad or boiled to remove bitterness.”

Also, “Wild lettuce produces a milky sap, called Lactucarium, from its leaves, stem, and roots when cut. Lactucarium is an analgesic and sedative. It has been used in the treatment of insomnia, osteoarthritis, and anxiety. The concentration of Lactucarium is highest when the plant is in bloom.”

-jsq