The Collaborative International Dictionary of English v.0.48:

mitrewort \mitrewort\ n.
   Any of various rhizomatous perennial herbs of the genus
   Mitella having a capsule resembling a bishop's miter. [Also
   spelled miterwort.]

   Syn: miterwort, bishop's cap.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

mitrewort
    n 1: any of various rhizomatous perennial herbs of the genus
         Mitella having a capsule resembling a bishop's miter [syn:
         miterwort, mitrewort, bishop's cap]