The Collaborative International Dictionary of English v.0.48:

Miterwort \Mi"ter*wort`\, n. (Bot.)
   Any plant of the genus Mitella, -- slender, perennial herbs
   with a pod slightly resembling a bishop's miter; bishop's
   cap.
   [1913 Webster]

   False miterwort, a white-flowered perennial herb of the
      United States (Tiarella cardifolia).
      [1913 Webster]