WordNet sense 1 (any coarse weed of the genus Xanthium having spiny burrs):

cockle-bur, cockleburr, cockle-burr

WordNet sense 2 (burdock having heart-shaped leaves found in open woodland, hedgerows and rough grassland of Europe (except extreme N) and Asia Minor; sometimes cultivated for medicinal and culinary use):

great burdock, Arctium lappa, greater burdock