"Porcupine egg" of cocklebur (Xanthium strumarium) near Onion Creek in McKinney Falls State Park. Austin, Texas, October 26, 2008
"Porcupine eggs" of cocklebur (Xanthium strumarium) at Lake Somerville Trailway near Birch Creek Unit of Somerville Lake State Park. Texas, July 19, 2020