A cluster of burdocks.
burdock definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
any of several plants (genus Arctium) of the composite family, with large basal leaves and purple-flowered heads covered with hooked prickles
Origin: bur plush dock
burdock definition by American Heritage Dictionary
Any of several weedy, chiefly biennial plants of the genus Arctium in the composite family, having pink or purplish flower heads surrounded by prickly bracts and forming a bur in fruit.
Origin: bur1 + dock4.