dry xanthium strumarium on white background has medicinal properties. top view. flat lay pattern

asteraceae barb brown bur burr californiabur closeup cocklebur compositae dangerous defense ditchbur dry features fruit heap herb hook isolated macro many mature medical needle pile plant pod pointed poisonous prickle prickly protect season seed seedpod spike spiny sticky strumarium thistle thorn thorny treatment weed white wildflower xanthium