Carbuncle, the Common Scabious for

"Take scabious, the green herb and bruise it. Apply this to the affected part. This has been found a very effectual remedy." The common field scabious have many hairy, soft, whitish green leaves, some of which are very small and rough on the edges, others have hairy green leaves deeply and finely divided and branched a little. Flowers size of small walnut and composed of many little ones. Sometimes called "Morning Bride," "Devil's Bit," etc.

Source: Mother's Remedies: Over One Thousand Tried and Tested Remidies from Mothers of the United States and Canada, T. J. Ritter