The game of Carl Doddies is played with the flower heads and stalks of the common plantain. My mother was brought up in Scotland and she must have taught us. It was said to have originated from a " beheading" game played in the Jacobite times, the names derived from Bonnie Prince Charlie, "Carl" and King George, "Doddie". You and your opponent each take a plantain flower and take it in turns to try to knock the head off their opponent's stem. Whoever beheads first is the winner. A variation is to loop the stem over itself and shoot the head as far as possible. The one that lands farthest away is the winner! .. a more civilized version of shot putting.
A more prosaic explanation of the name is simply "curly headed"