(from the article `teasel`) ...fruiting heads have been used since Roman times to raise the nap of woolen fabrics in a process known as fulling. The plant is raised commercially ...
[n] - teasel with lilac flowers native to Old World but naturalized in North America
Dipsacus fullonum noun teasel with lilac flowers native to Old World but naturalized in North America; dried flower heads used to raise a nap on woolen cloth