The Collaborative International Dictionary of English v.0.48:

Setterwort \Set"ter*wort`\, n. (Bot.)
   The bear's-foot (Helleborus f[oe]tidus); -- so called
   because the root was used in settering, or inserting setons
   into the dewlaps of cattle. Called also pegroots. --Dr.
   Prior.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Pegroots \Peg"roots`\ (p[e^]g"r[=oo]ts`), n.
   Same as Setterwort.
   [1913 Webster]